Heat oven to 200°F and place a metal rack over a baking sheet. (This will be used to keep the cooked pancakes warm while others are cooking.)
In a medium bowl, whisk together flour, baking powder, sugar and salt. Set aside.
In the bowl of an electric mixture, beat egg whites until stiff peaks form. Carefully transfer the beaten egg whites to a different bowl until ready to use.
In the same mixing bowl (no need to rinse it out), combine egg yolks, milk, cream, vanilla extract, lemon juice, lemon zest and 6 tablespoons melted butter. Mix until fully incorporated, about 2 minutes.
Add flour mixture to the egg yolk mixture and stir just until the dry ingredients are wet.
Gently fold in half of the beaten egg whites into the batter and then fold in the remaining half of the beaten egg whites. The egg whites should NOT be fully incorporated into the batter and the batter should look a little lumpy from the unincorporated beaten egg whites.
Heat a griddle until hot, over medium heat, and add 1 tablespoon butter. Pour 2 tablespoons batter, per pancake, onto the griddle. The griddle should hold 3-4 pancakes at one time.
Sprinkle fresh blueberries over the top of each pancake.
Once bubbles appear and begin to pop on the topsides on the pancakes, check the undersides to see if they are golden brown and carefully flip them over, with a spatula. Cook the other side 1-2 minutes or until they are golden on both sides and cooked through.
Transfer the pancakes to the prepared cooling rack/baking sheet and keep them warm in the oven until ready to serve.
Repeat the process with the remaining batter, adding extra butter when needed, until all pancakes are cooked.
To serve, drizzle with warm Creamy Lemon Syrup.