In a large mixing bowl, combine all the dry ingredients: oat flour, protein powder, cocoa powder, and salt. Whisk thoroughly to ensure the protein powder is evenly distributed and there are no lumps.

In a separate, microwave-safe bowl, gently warm the almond butter and maple syrup together for about 20-30 seconds until slightly runny. This makes mixing easier.

Pour the warmed almond butter mixture and vanilla extract into the dry ingredients bowl. Use a sturdy spatula to mix everything together until a thick, uniform dough forms that resembles brownie batter.

If the dough is too dry, add the milk one teaspoon at a time until the desired consistency is reached. If it's too sticky, add one teaspoon of oat flour. Fold in the chocolate chips, if using, now.

Roll the batter into uniform balls, about 1 to 1.5 inches in diameter (approximately 1 tablespoon each). Dust your hands lightly with extra cocoa powder if the mixture is sticky.

Place the finished protein bites on a parchment-lined plate or tray. Refrigerate for at least 30 minutes to allow them to firm up before serving. Store leftovers in an airtight container in the refrigerator for up to one week.