01 - Preheat oven to 350°F. Line a baking sheet with parchment paper.
02 - In a mixing bowl, combine softened butter, light brown sugar, and granulated sugar. Beat until the mixture is light and fluffy.
03 - Incorporate the egg and vanilla extract into the creamed mixture and beat until fully combined.
04 - Add flour, baking soda, and salt. Mix until just combined, then fold in semisweet chocolate chips.
05 - Slice each croissant horizontally, leaving a hinge so they open like a book.
06 - Fill each croissant with about 2 to 3 tablespoons of cookie dough and gently press closed.
07 - Place stuffed croissants on the prepared baking sheet. Optionally, brush tops with melted butter and sprinkle with mini chocolate chips.
08 - Bake for 15 to 20 minutes, until croissants are golden brown and the cookie dough is set but still soft.
09 - Let croissants cool slightly before serving warm for maximum gooeyness.