Flour swaps: Almond flour or all-purpose work 1:1. Oat flour gives the best texture.
Protein powder: Cookies and cream protein powder is the best call here — the flavor is even more on point.
Cookie swap: Any chocolate sandwich cookie works — Trader Joe's Joe-Joes, Newman-O's, or Back to Nature Classic Creme are great alternatives.
Sweetener: Swap coconut sugar for maple syrup or honey (start with 1 teaspoon).
Do not overcook. Slightly underdone is always better in a mug cake — pull it when the center looks just barely set.