Beat butter, white sugar, brown sugar, peppermint extract, vanilla extract, and salt together in a bowl using an electric mixer until smooth and creamy. Beat eggs into butter mixture until well incorporated.
Whisk flour, cocoa powder, and baking soda together in a bowl; gradually add to creamed butter mixture, beating until dough is well blended. Fold chocolate chips into dough. Drop dough by rounded teaspoons onto a baking sheet.
Bake in the preheated oven until cookies are set in the middle, 8 to 10 minutes. Cool cookies on the baking sheet for about 5 minutes before transferring to a wire rack to cool completely.