Heat a large, 12” skillet over medium-high heat then add Italian sausage and shallots and brown. Add garlic and Italian seasoning then saute for 1-2 minutes or until garlic is very fragrant. Add canned tomatoes, half & half, and gluten free gnocchi then bring mixture to a simmer. Turn heat down to medium then continue simmering until gnocchi are nearly tender, 7-8 minutes, stirring occasionally. Add baby spinach then stir to combine and continue cooking until spinach is wilted and gnocchi are tender, 1-2 minutes, adding splashes of chicken broth if necessary if sauce gets too thick. Remove skillet from heat then sprinkle in mozzarella cheese and stir to combine. Serve immediately.