Preheat your oven to 350°F (180°C) and line a baking sheet with parchment paper.
Lightly flour a surface and roll out the puff pastry. Cut it into equal-sized triangles.
Melt the dark chocolate in a double boiler or in the microwave. Mix with the butter and cognac until smooth.
If desired, add ground walnuts to the chocolate mixture for a richer flavor.
Place a small spoonful of the chocolate-cognac filling on the wider end of each pastry triangle. Roll them up into croissant shapes.
Place the croissants on the prepared baking sheet, ensuring the seam is facing down to prevent them from opening during baking.
Whisk together the egg yolk and milk, then brush the mixture over the tops of the croissants for a beautiful golden-brown color.
Bake the croissants for 15-18 minutes, or until golden brown and crispy.
Let them cool slightly on a wire rack, then dust with powdered sugar before serving.
To provide the best experiences, we and our partners use technologies like cookies to store and/or access device information. Consenting to these technologies will allow us and our partners to process personal data such as browsing behavior or unique IDs on this site and show (non-) personalized ads. Not consenting or withdrawing consent, may adversely affect certain features and functions.
Click below to consent to the above or make granular choices. Your choices will be applied to this site only. You can change your settings at any time, including withdrawing your consent, by using the toggles on the Cookie Policy, or by clicking on the manage consent button at the bottom of the screen.