These Boursin cheese and onion puff pastry appetizers are perfect for a cocktail hour or party. They’re simple to make but look and taste like something you’d order at a restaurant.

I made these for our Saturday evening cocktail hour, and they were a definite keeper. Using store-bought puff pastry made preparation easy, and I used just one sheet of pastry dough, which was still enough for two dinners.

The good news is that you can freeze these appetizers unbaked and cook the extras another day. We had our second batch the following weekend when my son came up for Thanksgiving, and they tasted just as good the second time around.

The first time we made these appetizers, we did a cocktail pairing experiment with a Gin & It and a French Gimlet. Both paired well with the savoury pastry, although we preferred the French Gimlet. We’ve discovered that we generally prefer cocktails with some citrus or juice rather than those made entirely with spirits and liqueurs.

INGREDIENTS

Makes approximately 25 appetizers, roughly 2×2 inches

• 1 sheet store-bought puff pastry, thawed according to package directions
• 1-2 large onions, thinly sliced (you need to end with 3/4 cup caramelized onions)
• 1 tbsp butter
• 1 tsp olive oil
• ¼ tsp salt, or to taste
• 4 oz Boursin cheese (slightly less than a full 5.2oz package)
• 1 egg yolk
• 1 tsp water or milk
• Fresh thyme leaves

METHOD

Note: check out my AI image below if you are a visual person like me. There are a lot of steps here, but when you see the image you realize it’s not that hard.

1. Caramelize the onions ahead of time. Heat the butter and olive oil in a skillet over medium-low heat. Add the sliced onion and salt. Cook slowly for approximately 25–35 minutes, stirring occasionally, until the onions are soft, golden brown and sweet. Reduce the heat if they begin to brown too quickly. You want the onions quite dry, with no excess moisture in the pan, so they don’t make the pastry soggy. Remove from the heat and allow to cool completely before assembling the appetizers.
2. When ready to bake. Preheat the oven to 400°F convection.
3. Unfold one sheet of thawed puff pastry onto a lightly floured surface. Work quickly to keep the pastry cold while working with it.
4. Using a sharp knife or pizza cutter, cut the pastry into approximately 2-inch squares. My pastry sheet was roughly 10 x 10 inches so I ended up with 25 quares.
5. Transfer the squares to a parchment-lined baking sheet, leaving a little space between them.
6. Using a small, sharp knife, lightly score a border approximately ¼ inch inside the edge of each square. Be careful not to cut all the way through the pastry. The scored border will puff up during baking, creating a raised edge around the filling.
7. Prick the centre of each square 2–3 times with a fork to help prevent the middle from puffing too much.
8. Place a heaping ½ teaspoon of cooled caramelized onions in the centre of each square.
9. Top with about 1 teaspoon of Boursin cheese. Don’t overfill the squares but it’s a balance. You want enough filling to provide flavour while leaving enough border for the pastry to rise and become crisp.
10. Top with fresh thyme leaves.
11. Whisk the egg yolk with 1 teaspoon of water or milk. Lightly brush the exposed pastry borders with the egg wash, avoiding the cut sides of the pastry. The egg yolk gives the finished pastry a deep golden colour.
12. When ready to eat, bake at 400°F convection for approximately 8-10 minutes, until the pastry is puffed, crisp and deeply golden brown.

Serve warm.

MAKE AHEAD & FREEZING

These appetizers freeze beautifully.

Assemble the pastry squares completely, including the onion and Boursin filling, but do not add the egg wash.

Place the assembled pastries on a parchment-lined baking sheet and freeze until solid.

Transfer to an airtight freezer container or freezer bag, separating layers with parchment paper. Freeze for up to 2–3 months for best quality.

To bake from frozen:

There is no need to thaw.

Arrange the frozen pastries on a parchment-lined baking sheet, brush the exposed pastry borders with egg wash, and bake at 400°F convection for approximately 10-12 minutes, or until puffed and golden brown.

RECIPE NOTES

• Keep the pastry cold. Puff pastry rises best when the butter layers remain cold before baking. If the pastry becomes too soft while assembling, refrigerate it for 10–15 minutes before baking. I made mine in the afternoon and kept them in the fridge until ready to bake.
• Cool the onions completely. Warm filling can soften the pastry before it goes into the oven.
• Don’t overload the filling. A small amount of onion and Boursin is all you need

I used ChatGPT one Saturday to help me create this appetizer as I wanted to use some Boursin cheese I had on hand. And because I’m a visual person, I asked the AI to create me an image of the steps involved in making this appetizer.  Looking at this image makes the process seem less overwhelming that a list of 12 steps. The image isn’t perfect in terms of steps, but it’s certainly helpful.