Preheat the oven to 350 F. Place a cast iron skillet in the oven as it pre-heats (any cast iron skillet 8-10 inches wide will work).
Divide egg yolks and whites. Add egg yolks, ricotta, milk, and vanilla to a medium mixing bowl. Mix until combined. To the same bowl add flour, baking powder, salt, and sugar.
Add egg whites to the bowl of a stand mixer. Whip until stiff peaks form (this can also be done with a hand mixer).
Open the oven and add the butter to the cast iron skillet so it can melt while you finish the batter.
Add the whipped egg whites to the mixture and gently fold everything together.
Carefully remove the hot cast iron skillet from the oven. Make sure the melted butter is covering most of the cast iron so the hotcake won't stick to the pan. Pour the batter into the cast iron skillet and transfer back to the oven.
Bake for 15-20 minutes, until toothpick comes out clean.
Place a large plate upside down on top of the cast iron skillet. Carefully flip the cast iron skillet over, while keeping the plate held to the skillet. Once its flipped, slowly lift up the cast iron skillet, leaving the hotcake on the plate.
To make the lemon mascarpone, add the mascarpone cheese and lemon zest to a bowl and stir until well combined.
To top the hotcake, add sunflower seeds, pecans, raspberries, blueberries, mint, and lemon mascarpone. Drizzle with maple syrup just before serving and enjoy!
(Feel free to use any toppings you want. Get creative and enjoy!)