1. Warm the milk a bit and mix with the yeast and 1 tsp. of the sugar until the yeast has completely dissolved.

2. Combine the flour, remaining sugar, and salt in the bowl of a food processor, then add the yeast milk, eggs, vanilla extract, and softened butter and knead everything into a smooth dough for about 8 minutes – it will be quite soft and a little sticky but that is ok. Let the dough rise, covered, in a warm place for about 1 hour.

3. While the dough is rising, chop the chocolate finely and set it aside. Line a baking sheet with parchment paper and set aside.

4. Roll out the risen dough on a lightly floured work surface into a rectangle of about 20×8 inches (50x20cm). Cut the rectangle into 5 strips, each strip about 4 inches (10cm) wide, then cut these strips diagonally into triangles. Spread about 1 tsp. caramel sauce onto the wide end of each triangle, place some chopped chocolate on top and roll up towards the tip of the triangle like a croissant. Place the croissants on the prepared baking sheet and cover with plastic wrap. Let rise again in a warm place for about 30 minutes.

5. Preheat the oven to 390°F (200°C). Mix the egg yolk with some milk, gently brush the croissants with it and then sprinkle with some coarse sugar. Bake for about 12 minutes – the croissants should have puffed up nicely with a golden brown color. Remove from the oven and allow to cool completely on the baking sheet for some time, then let cool completely on a wire rack.

6. If you like, you can drizzle the cooled croissants with some caramel sauce (you may want to warm the sauce first) and sprinkle them with chopped chocolate and some flaky sea salt (optional).