01 - Combine blueberries, sugar, water, and lemon juice in a small saucepan. Bring to a simmer over medium heat, stirring occasionally. Cook for 8-10 minutes until berries burst and syrup thickens slightly. Remove from heat and set aside.
02 - Whisk together ricotta, egg yolks, milk, lemon zest, lemon juice, vanilla extract, and melted butter in a large bowl until smooth.
03 - Whisk flour, sugar, baking powder, and salt in a separate bowl.
04 - Gently fold dry ingredients into the ricotta mixture until just combined. Do not overmix.
05 - Beat egg whites to stiff peaks in a clean bowl. Gently fold egg whites into the batter in two additions, maintaining as much air as possible.
06 - Heat a nonstick skillet or griddle over medium heat and brush with butter. Pour 1/4 cup batter per pancake. Cook 2-3 minutes until bubbles form on surface and edges look set, then flip and cook another 2 minutes until golden.
07 - Serve pancakes warm, topped with blueberry syrup.