Preheat oven: Preheat your oven to 350°F (175°C). Grease and flour a 9-inch springform pan or line it with parchment paper.
Beat eggs and sugar: In a large mixing bowl, beat the eggs and sugar together until light and fluffy.
Add wet ingredients: Add the melted and cooled butter, ricotta cheese, sour cream, and vanilla extract to the egg mixture. Mix until well combined.
Combine dry ingredients: In a separate bowl, whisk together the all-purpose flour, baking powder, and salt.
Add dry ingredients to wet ingredients: Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Add lemon zest and blueberries: Fold in the lemon zest and fresh blueberries, being careful not to crush the blueberries.
Pour batter into pan: Pour the batter into the prepared springform pan, spreading it out evenly.
Bake: Bake the cake in the preheated oven for 45-50 minutes, or until a toothpick inserted into the center comes out clean.
Cool and serve: Allow the cake to cool in the pan for about 10 minutes before removing it from the springform pan. Transfer the cake to a wire rack to cool completely. Serve the Lemon Blueberry Ricotta Cake at room temperature, with a dusting of powdered sugar or a dollop of whipped cream if desired.