Bring a large pot of water to a boil and add a pinch of salt. Add the broken spaghetti and cook until al dente according to package instructions. Drain well and set aside.
In a medium bowl, whisk together the eggs, grated Parmesan, 1/4 teaspoon salt, and 1/4 teaspoon black pepper until blended.
Heat 1 tablespoon olive oil in an 8–10 inch sauté pan over medium heat. Add the drained spaghetti and 1/4 cup marinara sauce and sauté briefly until heated through and combined.
Pour the egg mixture evenly over the spaghetti in the pan, tilting or stirring gently so the eggs distribute and coat the noodles.
Reduce heat to low, cover, and cook until the bottom is set and the frittata easily slides from the pan, about 4 minutes.
Carefully invert the frittata onto a plate, then slide it back into the pan to cook the other side until just set, about 3 minutes.
Slide the finished frittata onto a serving plate, slice, and serve warm.
