Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper. Slice each croissant in half horizontally to create a pocket for the cookie dough.
In a large bowl, cream the softened butter, granulated sugar, and brown sugar until light and fluffy. Beat in the eggs one at a time, then mix in the vanilla extract.
In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Fold in the chocolate chips.
Spread about 2–3 tablespoons of cookie dough inside each croissant and gently place the top half back on, allowing a little dough to peek out from the sides.
Arrange the filled croissants on the prepared baking sheet and bake for 20–22 minutes, or until the croissants are deep golden brown and the cookie dough is baked with a soft, gooey center.
Remove from the oven and let the crookies cool for 5 minutes before serving. Enjoy warm for the best flaky texture and melted chocolate.