Preheat oven to 425 degrees. Sprinkle bacon on bottom of tart shell. Combine eggs, cream, salt, nutmeg, and cayenne and beat thoroughly. Sprinkle cheese over bacon and ladle custard over all. Bake15 minutes at 425 degrees then lower heat to 350 degrees and bake 30 minutes more.
Spinach: Omit bacon and use only 1/2 cup cheese. Add 1 cup cooked, chopped spinach and 2 tbsp minced onion sauteed in 1 tbsp butter to custard.