Bring a large pot of salted water to a boil. Add the rotini and cook according to package instructions (usually about 8 to 10 minutes) until al dente. Drain but save about a cup of pasta water for later.

In a large skillet over medium heat, melt your butter. Once it’s bubbling, add the minced garlic and sauté for about 1 minute, or until fragrant.

Increase the heat to medium-high and add in the ground beef and Italian sausage. Cook, stirring occasionally until browned and fully cooked, about 7-10 minutes.

Stir in the fresh spinach and cook until wilted, around 2-3 minutes. Add splashes of reserved pasta water as needed.

Add the drained pasta to the skillet. Toss with the garlic butter sauce until coated, adding more pasta water if necessary.

Season with freshly cracked black pepper and crushed red pepper flakes, if desired. Remove from heat and sprinkle with freshly grated Parmesan cheese.