Step 1: Preheat the Oven and Prepare the Puff Pastry

Start by preheating your oven to 425°F (218°C). If you’re using frozen puff pastry, be sure to allow it to thaw according to the packaging instructions. Once it’s thawed, gently roll the pastry with a rolling pin to flatten it slightly. This helps the dough bake more evenly and ensures a perfectly crisp result.

If you’re using refrigerated puff pastry, you can skip this step—just make sure the pastry is cold when you work with it. This is important because puff pastry works best when kept cold, which helps the layers separate and puff up in the oven.

Next, cut each sheet of puff pastry into 4 equal squares, so you’ll have 8 squares in total. The squares should be about 5 inches on each side. If you want smaller croissants, you can cut the squares into even smaller pieces, but keep in mind that the baking time may change depending on the size.

Step 2: Shape the Croissants

Now it’s time to shape the croissants. Start by brushing each square of puff pastry with the whisked egg to give it a beautiful golden color once baked. Next, take one corner of each square and fold it over to form a triangle. Press the edges of the pastry firmly to seal them. You don’t want the filling to leak out, and sealing the edges will also help the pastry hold its shape as it bakes.

Brush the tops of the croissants with more egg wash for an extra golden finish. If you like, you can sprinkle the tops with coarse sugar, but this step is optional. The croissants will be delicious even without the added sweetness on top.

Step 3: Bake the Croissants

Place the prepared croissants on a baking sheet lined with parchment paper. This will make cleanup easier and prevent the croissants from sticking to the pan. Bake the croissants in your preheated oven for 22-25 minutes, or until they are a deep golden brown. Keep an eye on them, as puff pastry can brown quickly. If you’re using frozen puff pastry, you may need to bake them for a couple of extra minutes, while refrigerated pastry may cook a bit faster.

Once the croissants are done, remove them from the oven and let them cool completely on a wire rack. Don’t cut into them just yet! Letting them cool helps the puff pastry set, and you’ll be able to fill them with the cream and jam more easily.

Step 4: Make the Jam

While the croissants are baking, it’s the perfect time to make the jam. In a medium-sized saucepan, combine the frozen wild blueberries, granulated sugar, and lemon juice. Stir everything together and bring the mixture to a simmer over medium heat. Let it cook for about 15-20 minutes, stirring frequently to prevent burning. As the berries cook down, the jam will thicken. Keep an eye on it to make sure it doesn’t burn. Once the mixture has reached a thick, jam-like consistency, remove it from the heat and set it aside to cool.

If you’re using fresh berries, you’ll need to cook the jam for a little longer—about 5 extra minutes—since fresh berries have more water content than frozen ones. Don’t rush this step; allowing the jam to thicken naturally gives it a richer flavor.

Step 5: Prepare the Cream Filling

Now, onto the most decadent part: the cream filling. In a large mixing bowl, combine the cold heavy whipping cream, powdered sugar, and vanilla extract. Use a hand mixer to beat the cream until stiff peaks form. Be careful not to over-beat the cream, or it may turn into butter. Stiff peaks mean the cream holds its shape when you lift the beaters.

In a separate large bowl, beat the softened cream cheese and sour cream together until smooth and fluffy. This will only take about 1-2 minutes with a hand mixer. Once the cream cheese and sour cream are fully combined, gently fold in the whipped cream, one-third at a time. Continue folding until everything is fully incorporated. Taste the filling and adjust the sweetness if needed by adding more powdered sugar.

The cream filling can be made a day in advance and stored in an airtight container in the refrigerator. Just make sure to bring it to room temperature before using it, and give it a quick mix with a hand mixer to restore its fluffy texture.

Step 6: Assemble the Croissants

Once the croissants have cooled, use a sharp knife to cut each croissant in half, but not all the way through. You want the croissant to open like a book, with a little “hinge” at the bottom. Gently open the croissants and spread a generous amount of the homemade berry jam on both sides. The jam will add a burst of sweet, fruity flavor that pairs perfectly with the cream filling.

Next, spoon or pipe the cream filling into the croissants. Don’t be shy—there’s plenty of filling, and it’s the best part! The creamy, fluffy texture will complement the buttery puff pastry and sweet jam beautifully. Once filled, gently press the croissants back together and dust the tops with powdered sugar for that classic finishing touch.

Step 7: Serve and Enjoy

Serve the Berries and Cream Filled Croissants immediately while they’re still fresh and flaky. These croissants are best enjoyed right away, but you can store any leftovers in an airtight container for up to 2 days. However, keep in mind that the puff pastry will lose some of its crispness over time. To refresh the croissants, you can briefly reheat them in the oven to regain some of their original flakiness.