Blue Cheese and Steak Crostini with Blueberry Caramelized Onion Jam

Blue cheese and steak crostini with blueberry and caramelized red onion jam are hearty and savory with just a touch of sweetness. These easy, decadent appetizers are perfect for your next gathering!

Blue cheese and steak crostini with blueberry caramelized onion jam

I mentioned in my last post that we’ve recently decided it would be a great idea to have a weekly crostini night (like a fancy version of taco Tuesdays!) That idea was partly to benefit the blog, but mostly because I just can’t get enough of decadent toppings on little pieces of crusty toasted bread.

This blue cheese and steak crostini was the inaugural recipe for crostini night. I love a nice rare piece of beef, and blue cheese is a classic pairing for steak. Take the blue cheese, and what do you usually find next to it on a cheese board? A sweet jam or honey.

Now, I normally love fig jam with blue cheese, but I felt the steak called for something a bit richer and more complex.

My husband helped me think of the perfect jam to accompany the blue cheese for this crostini recipe – a savory caramelized red onion and blueberry jam, which includes splashes of balsamic vinegar and red wine.

I always see black and blue salads on menus at restaurants, so I thought it would be appropriate to sprinkle some arugula microgreens on top of these steak appetizer bites. Plus, they add the perfect pop of color! Other microgreens would also work for these, or even some radish sprouts. If you can’t find any of those, you could lay a couple pieces of arugula on the bottom of the crostini underneath the steak for a similar pop of color and flavor! 

This blue cheese and steak crostini is a bit more substantial than many canapes, making it hearty enough for a light dinner and perfect for a fall or winter appetizer. 

The Best Steak for Crostini

I chose a flank steak for this recipe because they’re easy to cook under the broiler and absolutely delicious when medium rare and thinly sliced. Just five minutes per side plus a five minute rest and they’re good to go.

Flank steak crostini with blue cheese and blueberry caramelized onion jam and arugula microrgreens

The first time I made these crostini, I marinated the flank steak in an enticing combination of red wine, soy sauce, brown sugar, and other ingredients. It was a truly amazing piece of meat – but it overcomplicated the recipe. It took longer to make because of the marinating time; plus, the flavor of the marinade competed with the blue cheese and jam flavor. You may see the marinade show up later on the blog, but not in this recipe!

So I made it again (oh, woe is me) with just a simple sprinkling of salt and pepper and a drizzle of olive oil on each side of the steak. Not only did it simplify the ingredient list and take less time, but my husband and I both agreed it was a much better match for the blue cheese and blueberry-caramelized red onion jam. A perfect combination of flavors!

What to Watch Out For When Making Blue Cheese and Steak Crostini

I bought a baguette with the best of intentions to make this recipe the next day. I never end up keeping those promises to myself, so it was two or three days later by the time I put these together.

By that time, the baguette was quite crusty and had far, FAR too much crunch. It was tooth- and ear-shattering, overwhelming the otherwise perfectly-balanced ensemble of steak, blue cheese, and onion-blueberry jam.

My husband couldn’t put his finger on why it wasn’t amazing, but I realized it might just be the bread.

Fortunately, I realized I had about a third of a loaf of much softer Italian bread in my bread box. On a whim, I sliced it up, painted it with some olive oil, and threw it under the broiler for a couple minutes. It had a little crunch – the perfect amount to contrast with the other textures. We both agreed it made the crostini just right!

That’s the thing about crostini recipes – they really have to blend together with just the right amount of complement and contrast. Too much contrast and the unity of the whole thing falls apart and it just feels wrong. It’s sort of an art.

Medium rare flank steak crostini appetizers with blue cheese and blueberry caramelized onion jam and arugula microgreens

The Anatomy of a Perfect Blue Cheese and Steak Crostini

Here’s how to assemble this blue cheese and steak crostini for best, most delicious results:

  • Toasty crostini – but not TOO crunchy. If you’re getting a shower of bread dandruff and the crunch is so loud you can’t hear your neighbor talk every time you take a bite, it’s too crunchy.
  • Plenty of medium rare steak, thinly sliced – This should be the dominant element in these crostini. Thinly slicing against the grain will make these super tender and delicious. Plus, you can get really nice little folds and drapes with thin slices that you don’t get with a thick slab. I don’t want you and your guests to have to gnaw through a thick slab of steak on what should be a delicate appetizer. Slice thinly!
  • Moderate amount of blue cheese crumbles – I used a buttermilk blue cheese. Use something that comes in a wedge, not a plastic tub of ready-to-go crumbles.
  • Just a little jam. Too much jam and it will overwhelm the other flavors. Make a sample crostini with the steak, blue cheese, and jam and test it out before you make the rest. It’s your right — and privilege! — as the cook to taste-test the crostini before you make the whole batch, in the name of testing. Then you’ll see if you need to add more or less jam to the rest of them!
  • Microgreens for added color and texture.

Flank steak crostini appetizers with blue cheese and blueberry caramelized onion jam

It’s very simple, and so satisfying! This is a great recipe for a heartier crostini recipe and would be perfect for a fall or winter gathering!

For more delicious crostini ideas, check out these recipes:

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Flank steak crostini appetizers with blue cheese and blueberry caramelized onion jam
4.67 from 3 votes

Blue Cheese and Steak Crostini with Blueberry and Caramelized Onion Jam

Blue cheese and flank steak crostini topped with blueberry balsamic and caramelized onion jam are hearty and savory with just a touch of sweetness! Try these easy, decadent appetizers for your next gathering!
Print Recipe Save Recipe
Course: Appetizer
Cuisine: American
Yield: 24 crostini
Calories: 128kcal
Prep Time:20 minutes
Cook Time:1 hour 10 minutes
Total Time:1 hour 30 minutes


For the crostini

  • 1 baguette or long Italian or French loaf not too crusty!
  • 1/4 cup olive oil
  • kosher salt

For the steak

  • 1 lb flank steak
  • 1 tbsp olive oil
  • kosher salt and pepper

For the blueberry and caramelized red onion jam

  • 1 tbsp olive oil
  • 1 medium red onion diced (about 2 cups)
  • several sprigs fresh thyme
  • 1/2 tsp kosher salt
  • 1/4 tsp freshly ground pepper
  • 2 cups blueberries
  • 2 tbsp balsamic vinegar
  • 1/4 cup honey
  • 2 tbsp brown sugar
  • 1/4 cup red wine
  • 1 tsp lemon juice

For assembling

  • 4 oz wedge blue cheese
  • arugula microgreens can use other microgreens, radish sprouts, or baby arugula


  • Follow instructions for making Savory Blueberry and Caramelized Onion Jam. Allow at least an hour to make jam and let it cool before beginning the next step. This step can be done several days in advance.
  • Preheat oven to 375 degrees Fahrenheit. Slice bread into 1/3-1/2-inch slices and arrange on a sheet pan. Brush slices with olive oil and sprinkle with kosher salt. Bake for 7-10 minutes, or until crispy on top. Set aside crostini. Note: Crostini may not brown, and that's okay! Don't keep baking it until it's brown, or it will end up far too crunchy. Alternately, you can put it under the broiler for a 2-4 minutes instead of baking at 375 to get more browning on top, if that's important to you! 
  • Turn oven to broiler and set top rack to about 4-6 inches away from the heating element (I do the second from the top position on mine). Pat flank steak dry with paper towels. Then drizzle olive oil on both sides of steak and rub in gently. Sprinkle on both sides with kosher salt and black pepper and put steak on a sheet pan.
  • Cook steak under the broiler for about 5 minutes per side, until medium rare. Then let it rest for another 5 minutes so it will stay juicy when you slice it! Slice as thinly as possible against the grain.
  • Top crostini pieces with several (2-3) slices of steak, folded and draped decoratively. Then add a couple blue cheese crumbles, a small dollop of jam, and a pinch of microgreens. Note: Taste one first to make sure the ratios are all good before you make the whole batch! It's easy to overwhelm the steak with too much blue cheese or jam. If using baby arugula instead of microgreens, layer them on the bottom of the crostini before adding the steak.
  • Enjoy along with wine and a cheese board!
Tried this recipe?Mention @pinchmeimeating or tag #pinchmeimeating on Instagram!


Calories: 128kcal | Carbohydrates: 12g | Protein: 6g | Fat: 6g | Saturated Fat: 2g | Cholesterol: 15mg | Sodium: 189mg | Potassium: 113mg | Fiber: 1g | Sugar: 6g | Vitamin A: 43IU | Vitamin C: 2mg | Calcium: 41mg | Iron: 1mg

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  1. Thinking of doing this with a wine pairing event. I’am about 45 minutes from the event so what do you think about preparing earlier in the day and then assembling when I get there? Should the beef be served warm or at room temperature?

  2. 5 stars
    This recipe was delicious. We had a tapas party and everyone loves it. We also served the recipe without the crostini for a gluten free alternative. Thanks!

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