Caramelized Onion & Brussels Sprouts Tarts

  • Author: Midwest Foodie
  • Prep Time: 10 minutes
  • Cook Time: 40 minutes
  • Total Time: 50 minutes
  • Yield: 18 tarts 1x
  • Category: Appetizer
  • Method: Oven
  • Cuisine: American


These little squares of heaven have a buttery, flaky puff pastry dough crust with quick caramelized onion, sliced Brussels sprouts, crumbled blue cheese and a fruity burst from pomegranate seeds.    



  • 1 (17.3 oz.) package (2 sheets) puff pastry, thawed
  • 2.5 tablespoons butter
  • splash dry white wine
  • 1 yellow onion, halved and sliced in 1/8″ thick slices
  • about 1 cup 1/8-1/4″ thick sliced Brussels sprouts
  • 5 oz. crumbled blue cheese
  • 1 beaten egg + splash of water
  • 1/2 cup pomegranate seeds
  • Kosher salt


  1. Heat butter in a large pot over medium heat. Add onion along with a pinch of salt. Cook for 20 minutes, stirring every few, until the onions are brown and caramelized. Deglaze the pan with a splash of white wine and scrape all the yummy bits off the bottom. Set aside. 
  2. Preheat oven to 400 degrees.
  3. Unfold puff pastry and cut along the seams, creating 6 rectangles. Cut each rectangle into 3 squares. 
  4. Place squares on a parchment lined baking sheet. Score the squares with a knife about a 1/2″ from the edge, creating the crust. 
  5. Divide caramelized onion evenly between the tarts. 
  6. Divide Brussels sprouts evenly between the tarts. 
  7. Divide blue cheese evenly between the tarts, reserving 1-2 tablespoons for garnish. 
  8. Brush the crust of each tart with the egg wash. 
  9. Bake for 18-20 minutes or until the edges and bottom of the dark are golden brown. 
  10. Garnish with pomegranate seeds and the remaining blue cheese. 
  11. Serve warm or at room temperature and enjoy!


The easiest way to thaw puff pastry is in the fridge overnight. If you don’t have time to do that, you can leave it out on the counter for about 40 minutes or so. 

Keywords: puff pastry tart, caramelized onion tart, Brussels sprouts tart