Bring a large pot of salted water to a boil.
Cook the tortellini according to package directions, adding the frozen peas for the last minute of cooking time.
Drain the tortellini and peas, and return them to the warm pot.
Meanwhile, in a medium saucepan, whisk together the flour and pepper. Slowly stream in the half-and-half, whisking continuously to create a smooth mixture.
Place over medium heat and cook, stirring often, until the sauce thickens and bubbles.
Cook for 1 minute more, then gradually stir in the undrained diced tomatoes.
Season to taste with salt and more pepper.
Pour the creamy tomato sauce over the tortellini and peas in the pot.
Toss gently to coat everything evenly.
Divide among four bowls and top each serving with a sprinkle of Parmesan cheese before serving.
Stir in a few large handfuls of fresh spinach with the sauce and let it wilt for an extra boost of nutrients and color.
