Melt butter in a large pan over medium heat. To brown the butter and separate the milk deposits on the bottom, swirl it with a rubber spatula. Approximately 10 minutes. Stop cooking immediately.
1
Mix the butter in a large basin. Let it sit 15 minutes.Preheat oven to 350°F. Prepare two baking sheets with parchment. Set aside.
2
Sift flour into a large basin by itself. Mix in baking powder, soda, and salt.Mix brown sugar and sugar in the browned butter basin. Add vanilla and eggs. Mix in dry ingredients.
3
Add chocolate chips. Large (3oz) cookie scoops provide 6 dough balls per sheet.Bake each sheet for 11 minutes. Cut marshmallows in half. On each warm biscuit, place 1-2 marshmallow halves. Return to oven for 2-3 minutes.
4
Lightly "smush" marshmallows with your fingertips. Add more chocolate chips to cookies.Transfer the cookies to a cooling rack after 5 minutes on the heated tray. Dig in after 10 minutes of cooling.
5