In a small saucepan, combine the mixed berries, 1 teaspoon of lemon juice, and maple syrup over medium heat until the fruit softens and the sauce is bubbling.
In a medium mixing bowl, whisk together the Greek yogurt, egg whites, vanilla extract, and the remaining 1 teaspoon of lemon juice until the mixture is smooth.
Gently stir in the oat flour, vanilla protein powder, baking powder, and sea salt until just combined, being careful not to overmix the batter.
Heat the coconut oil in a large non-stick skillet or griddle over medium-low heat.
Scoop the batter onto the skillet in 1/4 cup portions, leaving space between each pancake.
Cook for 2-3 minutes until small bubbles form on the surface, then flip and cook for another 1-2 minutes until golden brown and fluffy.
Serve the warm pancakes immediately, topped generously with the prepared berry compote.