Wash hands with soap and water for 20 seconds.
Pour milk into a liquid measuring cup that will hold at least 2 cups. Add vinegar or lemon juice and put aside until needed.
Heat a non-stick griddle to medium-low.
In a medium bowl, combine flour, protein powder, cocoa powder, stevia-blend sweetener, cinnamon, baking powder, baking soda, and salt. Whisk thoroughly to combine, breaking up any lumps in the protein or cocoa powder.
Retrieve the measuring cup with the milk-vinegar mixture. Add the egg, vegetable oil, and vanilla. Beat with a whisk until smooth.
Make a well in the center of the dry ingredients. Pour in the wet ingredients. Whisk lightly until combined, being careful not to overbeat. The batter should not be perfectly smooth.
Let the batter sit for 3 to 5 minutes, and then pour about ⅕ cup of batter on the hot griddle to make a pancake about 4 inches in diameter.Cook on griddle until the pancake is lightly set, with slightly dry edges and a few bubbles forming on top. (At this point, you can add extras like shredded coconut, mini chocolate chips, and/or toasted nuts to the cakes.) Flip, and allow to cook for a minute or two before removing to a warm plate.
Continue cooking pancakes until all the batter is used. Serve with syrup, chocolate yogurt sauce, and/or berries.