Mix dry ingredients. In a medium bowl, whisk together the protein powder, cocoa powder, and a small pinch of salt.
This helps prevent clumps.
Add the base. Stir in the Greek yogurt and vanilla until mostly smooth. It will look thick—totally normal.
Sweeten and enrich. Add the nut butter and maple syrup. Mix until glossy and uniform.
Adjust texture. Add milk 1 tablespoon at a time, stirring after each addition, until you reach a creamy, dip-able consistency.
Aim for thick brownie batter.
Taste and tweak. Add more sweetener if you like, or a dash more cocoa for extra intensity. Fold in any optional add-ins.
Serve. Spoon into a bowl and top with a few chocolate chips or a sprinkle of cocoa. Serve with fruit, pretzels, or whatever you love to dip.