01 -
Slice the Italian sausage, dice the onion, mince the garlic, and measure out all ingredients before starting.
02 -
Heat a large, deep skillet or Dutch oven over medium-high heat with a splash of oil. Sauté the sausage slices until browned and cooked through.
03 -
Add the diced onion and minced garlic to the pan. Cook until the onion softens and the mixture becomes fragrant.
04 -
Stir in the penne pasta, chicken broth, canned diced tomatoes with their juices, and tomato paste. Mix thoroughly to combine.
05 -
Bring the mixture to a boil, then reduce heat to low. Simmer uncovered, stirring occasionally, for 12–15 minutes, until the pasta is al dente and most of the liquid is absorbed.
06 -
Fold in the shredded mozzarella and grated Parmesan cheese. Stir until both cheeses are melted and evenly distributed.
07 -
Adjust seasoning with salt and black pepper. If using, stir in fresh spinach until wilted or add cherry tomatoes before serving.