Preheat oven to 325ºF. Evenly coat 4 (6 oz.) custard cups with cooking spray. Press about 1/4 cup spinach into each cup. With back of spoon, make an indentation in center of spinach. Break and slip an egg into each indentation. Top each with 1 tablespoon salsa and 1 tablespoon cheese. Bake until whites are completely set and yolks begin to thicken but are not hard, about 20 to 25 minutes. Top with sour cream and/or additional salsa, if desired.

Nutritional information per serving of 1/4 recipe without optional ingredients: 130 calories, 10g protein, 4g carbohydrate, 8g total fat, 220mg cholesterol, 258mg sodium.