Nutella-Stuffed Red Velvet Skillet Cookie

Preheat oven to 350 degrees F and butter a 5" cast-iron skillet. In a stand mixer with the paddle attachment, cream butter and sugars until light and fluffy, scraping down sides of bowl as needed. Continue mixing and add egg, vanilla, vinegar, and food coloring. Scrape down bowl with a spatula. In a medium bowl, whisk together flour, cocoa powder, baking soda, and salt. With the stand mixer on low, slowly add flour mixture until just combined (be careful to not over mix.) Fold in chocolate chips. Place a heaping 1/2 cup of dough into skillet and spread until it covers the bottom. Spread dough with Nutella, leaving 1/4" around edges, then add another layer of cookie dough, completely covering Nutella. (You won't need to use all the dough; the skillet will overflow. Use remaining dough to make 3 to 5 cookies.) Bake until cookie top no longer looks doughy and edges begin to brown, 20 to 25 minutes. Serve warm topped with ice cream.