Cook pasta according to package instructions, omitting salt and fat. Drain pasta, reserving 1/2 cup pasta water.
Melt butter in a large nonstick skillet over medium-high heat. Add garlic; sauté 30 seconds. Add reserved pasta water and cream cheese, stirring with a whisk until smooth.
Combine broth and flour in a small bowl, stirring with a whisk until smooth. Add flour mixture to pan, stirring with a whisk to combine; bring to a boil. Cook 2 minutes or until mixture thickens, stirring constantly. Remove from heat; add pecorino Romano, stirring until smooth. Add half-and-half, salt, and pepper. Stir in spinach. Combine cheese mixture and pasta in a large bowl, tossing to coat. Place about 1 cup pasta mixture in each of 8 bowls; top each serving with 2 1/2 tablespoons bacon. Garnish with parsley, if desired.