Mix the dry ingredients: Whisk flour, protein powder, poppy seeds, baking powder, salt, sugar (if using), and lemon zest in a large bowl.
Blend the wet ingredients: Add cottage cheese, eggs, milk, lemon juice, vanilla, and oil to a blender. Blend until mostly smooth.
Combine the batter: Pour blended wet ingredients into the dry ingredients. Stir gently until just combined. Let batter rest 5 minutes so the protein powder hydrates. Add 1–2 tablespoons extra milk if the batter becomes too thick.
Cook the pancakes: Heat a lightly greased skillet over medium heat. Pour about ⅓ cup batter per pancake. Cook until bubbles form and edges begin to set, about 2–3 minutes. Flip and cook another 1–2 minutes until golden.