Heat a large, deep skillet over medium-high heat. Cook and stir sausage in the hot skillet until slightly cooked, about 3 minutes. Add garlic and rosemary; continue to cook until sausage is browned and crumbly, 3 to 5 more minutes. Remove to a mixing bowl with a slotted spoon, leaving drippings in the pan and the heat set at medium-high.
Stir butter into the pan until melted. Gradually whisk in flour until smooth. Reduce heat to medium and cook until flour is light brown, 3 to 5 minutes. Gradually whisk in water, cream, and maple syrup and cook until gravy has thickened, 3 to 5 more minutes.
Meanwhile, crumble sausage into smaller bits.
Once gravy has fully thickened, stir in cooked sausage and ricotta cheese. Reduce heat and simmer for 12 to 15 more minutes until the consistency is like sour cream. If gravy is too thin, whisk in more flour, 1 tablespoon at a time.