Instructions

1. Preheat the oven to 350°F and grease a standard muffin tin with baking spray. Set aside.
2. In a large bowl, add the melted butter and let it cool slightly. Add the granulated sugar and light brown sugar and whisk until combined. Add the egg and vanilla extract and whisk until smooth.
3. Stir together the flour, cornstarch, baking soda, and salt, then add the dry ingredients to the wet mixture. Mix just until evenly combined, scraping the bottom of the bowl to incorporate everything well. Fold in the chocolate chips.
4. Drop one rounded tablespoon of dough (about 40 grams) into each cavity of the muffin pan and press down gently with the back of a spoon to flatten.
5. Bake for 12 to 15 minutes, until the edges are lightly golden. The centers will remain slightly soft.
6. Immediately after removing from the oven, press the center of each cookie cup with the back of a tablespoon or a 1/8 cup measuring cup to create an indent for the filling. Let the cookie cups cool completely in the pan.
7. Once fully cooled, they should release easily from the edges. If any stick, run a butter knife around the sides, gently twist to loosen, and lift them out.
8. Spoon Nutella or your preferred filling into each cup.
9. Allow the filled cookie cups to cool completely before storing. Store in an airtight container at room temperature for up to 5 to 6 days to prevent them from becoming soggy.