In a large pot of salted boiling water, cook the bowtie pasta according to package instructions until al dente. Reserve ½ cup of pasta water, then drain and set aside.
In a large skillet, heat the olive oil over medium heat. Add the chopped onion and sauté for 2-3 minutes until translucent.
Stir in the minced garlic and ground beef. Cook until the beef is browned and cooked through, breaking it apart as it cooks; this should take about 5-7 minutes. Season with salt, pepper, and Italian seasoning.
Lower the heat to medium-low and add the heavy cream to the skillet. Stir well, allowing it to come to a gentle simmer. Gradually add the grated Parmesan cheese, stirring until melted and well incorporated.
Add the cooked bowtie pasta and chopped spinach to the skillet. Toss everything together to combine, adding reserved pasta water a little at a time to achieve your desired sauce consistency.
Taste and adjust seasoning if necessary. Serve hot, garnished with fresh parsley and a sprinkle of additional Parmesan cheese if desired.
Notes
Adjust seasoning to taste and add more Parmesan if desired.