Coat 4 (12-ounce) microwave-safe mugs with cooking spray.
Crack 2 eggs into each prepared mug.
Add 1 tablespoon half-and-half to each; whisk with a fork until completely blended.
Add 2 tablespoons spinach, 1 tablespoon feta and 1½ teaspoons dill to each mug, stirring until combined.
Sprinkle with salt.
Cover and refrigerate for up to 4 days.
When ready to eat, uncover a mug and microwave on High, stirring every 15 to 20 seconds, until set, 1 minute and 15 seconds to 1 minute and 25 seconds for large curds (about 1 minute for soft-scramble).
Stir with a fork to create fluffy curds.
Sprinkle with additional dill, if desired.
