In a large bowl, whisk together the vanilla whey protein powder, all-purpose flour, granulated sugar, baking powder, and salt until no lumps remain.
In a separate bowl, whisk the egg, milk, melted unsalted butter (or neutral oil), and vanilla extract until fully combined.
Pour the wet ingredients into the dry ingredients and gently stir with a spatula just until flour streaks disappear, leaving a few small lumps.
Heat a non-stick griddle or large skillet over medium-low heat and lightly grease with butter or cooking spray.
Pour about 1/4 cup of batter per pancake onto the hot griddle. Cook for 2–3 minutes, until bubbles form on the surface and edges look set.
Carefully flip each pancake and cook for another 1–2 minutes on the second side, until golden brown and cooked through.
Transfer cooked pancakes to a plate and keep warm. Repeat with remaining batter, greasing the pan lightly between batches, then serve warm.