Bloom your protein powder in a splash of milk before mixing — this is the single step that eliminates grittiness. Toast the Nilla wafers in a dry pan for two minutes until deeply fragrant. Keep the crumbs separate until serving to preserve crunch. Use full-fat Greek yogurt; non-fat will break and turn watery. Adjust protein powder amount based on brand — start with 3/4 scoop. The yogurt base lasts up to 3 days in the fridge; add fresh banana and crumbs each morning.