Prep the pan: Preheat your oven to 350°F (175°C). Lightly grease a 12-cup muffin tin or line with silicone baking cups for easy release.
Wilt the spinach (if using fresh): Warm 1 tablespoon oil in a skillet over medium heat. Sauté spinach for 1–2 minutes until just wilted.
Let cool slightly, then squeeze out excess moisture. If using frozen, thaw completely and squeeze dry.
Whisk the eggs: In a large bowl, whisk eggs, heavy cream, salt, and pepper until smooth and slightly frothy.
Season: Stir in garlic powder, onion powder, and smoked paprika. This keeps flavor consistent throughout the bites.
Add the mix-ins: Fold in spinach, cheddar, Parmesan, green onion, and optional cooked meats.
Drizzle in remaining oil or butter for extra richness.
Fill the cups: Divide the mixture evenly among the muffin wells, filling each about 3/4 full. Give the tin a gentle tap on the counter to settle everything.
Bake: Bake 16–20 minutes, until the centers are just set and the edges are lightly golden. A toothpick should come out mostly clean with a few moist bits.
Cool briefly: Let the bites rest in the pan for 5 minutes to firm up.
Then run a thin knife around the edges and lift out.
Serve: Enjoy warm as is, or top with a dollop of sour cream, a sprinkle of herbs, or a dash of hot sauce.