Suki's Spinach and Feta Pasta

Bring a large pot of lightly salted water to a boil.

Cook pasta in boiling water until al dente; drain.

Meanwhile, heat olive oil in a large skillet over medium-high heat; add onion and garlic, and cook until golden brown.

Mix in tomatoes, mushrooms, and spinach.

Season with salt, pepper, and red pepper flakes.

Cook 2 minutes more, until tomatoes are heated through and spinach is wilted.

Reduce heat to medium, stir in pasta and feta cheese, and cook until heated through.