Preheat oven to 350°F.

Heat oil in an oven-proof skillet, preferably cast iron, over medium heat. Add garlic, onion and red pepper flakes and sauté until the onions are translucent. Add zucchini noodles and sauté for 2 minutes.

In a large bowl, whisk together eggs, milk, Parmesan, and salt. Pour into skillet over zucchini noodles. Flatten any stray zoodles down with a spatula or spoon and transfer the skillet to the preheated oven for 20-30 minutes, or until a knife comes out clean. If you want a little extra color on top at the end, you can broil it for 2 minutes. Let cool slightly before cutting.

To serve, cut frittata into wedges and serve with tomato wedges alongside. Sprinkle torn basil leaves on top of frittata, drizzle with aged balsamic and an extra sprinkle of Parmesan cheese.