Preheat the oven to 350 degrees F (175 degrees C).
Bring a pan of lightly salted water to a boil. Add
the pasta, and cook until tender, about 8 minutes.
Crumble ground beef into a skillet over medium-
high heat. Cook, stirring constantly until evenly
browned. Drain excess grease, and stir in the
tomato sauce, sour cream and thyme.
Place the cooked pasta into the bottom of a 2
quart casserole dish. Pour the ground beef mixture
over the pasta. Cover with a layer of spinach. Top
with shredded cheese.
Bake for 30 minutes in the preheated oven, until
heated through and lightly browned on the top.