Melt 4 tablespoons of butter and set aside to cool.
Add the sugar to a large bowl, then grate the zest of the lemon directly into the sugar. Using your fingers, gently rub the zest into the sugar to release all of the lemon oils into the sugar.
Whisk the flour, sugar, baking powder, baking soda, and salt together in a large bowl.
In a large measuring cup, whisk the milk, eggs, and vanilla. Add the ricotta cheese and lemon juice and mix until thoroughly combined. For smoother texture, use a standing blender or immersion blender to fully mix.
Pour the wet ingredients into the dry ingredients and fold together until combined. Add the cooled, melted butter and mix until well combined. Set aside to rest for 10 minutes.
Heat a large cast iron griddle or nonstick skillet over medium-low heat. When warm, add a teaspoon or so of butter and let melt. Drop ¼ cup scoops of pancake batter onto griddle or pan.
Drop a few whole fresh blueberries on top of each and give them a little push into the pancake. After 2-3 minutes, bubbles will start to form on the edges and surface of the pancake.
When the edges look dry and surface bubbles begin to pop, use a thin pancake spatula to gently lift one side and peek underneath. If the pancake is golden brown, flip and cook on the other side for 2 to 2 ½ minutes, or until the bottom of the pancake is golden brown.
Place cooked pancakes in a pancake or tortilla warmer, or on a plate with a large bowl turned upside down over the top, to keep them warm.
Serve with warm maple syrup and more fresh blueberries.