To prepare the syrup: In a medium saucepan, combine berries, water, sugar and lemon juice; bring to a boil over medium heat. Reduce heat and simmer berries until juices are thick and reduced, about 10 minutes. Using a hand blender or in a standard blender, puree the berries until smooth. Pass mixture through a fine-mesh sieve using a spatula to press mixture through; discard seeds. Taste and adjust with sugar and lemon juice. Transfer mixture to a syrup pitcher and set aside.

To prepare the pancakes: In a small bowl, whisk together ricotta, egg yolks, milk, vanilla, and lemon zest until well combined; set aside.

In a medium bowl, sift together the flour, baking powder, salt, and sugar. Stir the ricotta mixture into the flour mixture until just combined.

In the bowl of a stand mixer fitted with a wire whip attachment, whip the egg whites on medium-high speed until they form stiff peaks. Using a silicone spatula, gently fold one-third of the egg whites into the ricotta batter to lighten the mixture. Fold in the remaining whites just until there are no more streaks of white.

Preheat a large GreenPan skillet over medium heat and brush lightly with melted butter using a silicone pastry brush. Working in batches, ladle ¼ cup of batter per pancake onto the skillet; cook for about 2 minutes or until the top begins to bubble and edges start to become golden. Using a spatula, flip the pancakes and cook another 1 to 2 minutes, or until golden brown and the center is cooked through.

To serve: Place pancakes on a warm serving plate. Spoon the blackberry syrup over the top of the pancakes and serve immediately.