1. Thaw spinach; drain well, pressing between paper towels.
2. Cook sausage in a large skillet over medium-high heat, stirring often, 5 minutes or until sausage crumbles and is no longer pink; remove from skillet, and drain.
3. Preheat oven to 350°. Bring broth, cream, and salt to a boil in a large saucepan over medium-high heat. Gradually whisk in grits, and return to a boil. Cover, reduce heat to medium-low, and simmer, whisking occasionally, 12 to 15 minutes or until thickened. Remove from heat; stir in Asiago, pepper, and 3/4 cup Cheddar until melted. (Mixture will be very thick.)
4. Gradually stir about one-fourth of hot grits into eggs; stir egg mixture into remaining hot grits. Stir in spinach and sausage until blended.
5. Sprinkle bottom and sides of a lightly greased 10-inch deep-dish pie plate with cornmeal. Spoon grits mixture into pie plate; sprinkle with remaining Cheddar cheese.
6. Bake at 350° for 55 minutes or until set. Remove from oven to a wire rack, and cool 30 minutes.
To Freeze: Prepare recipe as directed through Step 5. Cover tightly with plastic wrap and heavy-duty aluminum foil. Place quiche in a 2-gal. zip-top plastic freezer bag. Freeze up to 1 month. Thaw in refrigerator 24 hours. Let stand at room temperature 30 minutes, and bake as directed.
Note: Recipe may be doubled and baked in a 13- x 9-inch baking dish for 1 hour.