Whisk dry ingredients: In a large bowl, whisk flour, protein powder, sugar, baking powder, baking soda, and salt until combined.
Mix wet ingredients: In a separate bowl, whisk buttermilk, Greek yogurt, egg, and vanilla until smooth.
Stir in lemon zest if using.
Combine gently: Pour wet into dry. Stir with a spatula just until the flour streaks disappear. The batter should be thick and a bit lumpy.
Fold in blueberries: Gently fold in the berries to avoid smashing them.
If using frozen berries, add them straight from the freezer.
Rest the batter: Let it sit for 5 minutes. This helps the flour hydrate and the pancakes rise better.
Heat the pan: Warm a nonstick skillet or griddle over medium heat. Lightly coat with butter or oil.
Portion and cook: Scoop 1/4 cup batter per pancake.
Cook until bubbles form and edges look set, about 2–3 minutes. Flip and cook 1–2 minutes more.
Adjust heat as needed: If they brown too fast, lower the heat. Wipe and re-grease the pan between batches if berries stick.
Serve warm: Stack with a pat of butter, a drizzle of maple syrup, and extra blueberries.