01 - Preheat the oven to 375 degrees Fahrenheit.
02 - In a medium mixing bowl, whisk together eggs, whole milk, grated Parmesan cheese, salt, and black pepper until fully combined.
03 - Heat olive oil in a 10-inch oven-safe skillet over medium heat. Add shallot, if using, and cook for 2 to 3 minutes until softened.
04 - Add halved cherry tomatoes to the skillet and cook for 2 minutes until just starting to soften.
05 - Pour the egg mixture into the skillet and gently stir to evenly distribute the vegetables.
06 - Dollop ricotta cheese by spoonfuls over the eggs. Sprinkle chopped basil and red pepper flakes, if desired.
07 - Cook over medium heat for 3 to 4 minutes until the edges begin to set.
08 - Transfer the skillet to the oven and bake for 10 to 12 minutes, or until puffed and just set in the center.
09 - Remove from the oven, allow to rest for 2 minutes, then slice and serve warm.