Please read my blog post for helpful instructions and notes before beginning.
Preheat the oven to 425°F / 218°C. If using frozen puff pastry, thaw per packaging instructions. It should be manageable to use but still cold to the touch. Use a rolling pin to gently flatten the sheets a bit. If using refrigerated puff pastry, skip this step.
2 sheets pre-made puff pastry
Depending on the size of your puff pastry sheets, cut each sheet into 4 equal squares so you have 8 squares total. The squares should be about 5 inches on all sides. Feel free to cut into smaller squares but baking time and results may vary.
Brush each square with egg wash, then grab one corner and fold into a triangle. Press and seal the edges to ensure it doesn't pop open too much in the oven. Brush the tops with more egg wash. Sprinkle with coarse sugar or leave it as it.
1 egg
Bake for 22-25 minutes until deep, golden brown. Set aside to cool completely. Do not cut the croissants just yet. Please see note below.Note: I noticed when I use frozen puff pasty, they need a few minutes longer to bake in the oven. Refrigerator puff pastry takes a few minutes less. Keep an eye on the puff pastry color at the 22 minute mark and monitor the color/bake after that. While the croissants are baking, make the jam. To a pot over medium heat, add frozen berries, fresh berries, sugar and lemon juice.
2 cups frozen blueberries, 1/2 cup fresh blackberries, 1/2 cup granulated sugar, Juice of 1/2 small lemon, 1/2 cup fresh raspberries
Bring to a simmer. Cook over medium-high heat for 15-20 minutes until the fruit is dissolved and the juices are thickened. Stir frequently. Keep an eye closely to avoid burning the jam. Don't rush this step. Set aside to cool as it will continue to thicken.Note: If using fresh fruit, cook the jam for an additional 5 minutes to reduce as fresh fruit has higher water content than frozen. While the croissants are baking, make the cream. To a large mixing bowl, add cold heavy cream, powdered sugar and vanilla extract. Use a hand mixer to beat until stiff peaks form. To a separate large mixing bowl, add cream cheese and sour cream. Use a hand mixer for 1-2 minutes and beat until fluffy, creamy and combined. Then, gently fold in 1/3 of the whipped cream at a time to the cream cheese mixture. Continue folding until fully combined. Taste and adjust sweetness per preference. Note: You can make the filling up to one day ahead. Store in an airtight container in the refrigerator. Just make sure to bring it to room temperature and give it a good mix with the hand mixer before using to fluff it up again. It naturally becomes stiffer when chilled. 2 cups heavy whipping cream, 8 ounces cream cheese, 2 Tablespoons sour cream, 3/4 cup powdered sugar, 1 teaspoon vanilla extract
Use a sharp knife to cut each croissant in half but not all the way through. Gently open and spread a generous amount of jam on both sides. Fill with cream filling. Don't be shy! This recipe makes extra filling on purpose. It's the best part of this dessert. Close and dust the tops with powdered sugar. Best served immediately.
1 Tablespoon powdered sugar