Creamy Sausage and Spinach with Whole Wheat Rotini

Name: Creamy Sausage and Spinach with Whole Wheat Rotini
Ingredients: 2 garlic and herb pork sausages; 1 tablespoon grapeseed oil; 1 tablespoon butter; 2 tablespoons all purpose flour; 1 cup milk; 1 clove of garlic, smashed; 1/2 cup grated Parmesan cheese in two, 1/4 cup portions; 1 pinch fresh ground pepper (to taste); 1 pinch salt (to taste); 3 cups frozen chopped spinach (thaw and squeeze off most of the liquid if it's in a brick, or add frozen if it's in a bag and not stuck together); 2 cups whole wheat rotini