Prepare the Mug: Lightly spray a microwave-safe mug with cooking spray or brush it with a little olive oil to prevent sticking.
Mix the Base: In the mug, crack the large eggs and add the tablespoons of milk. Whisk together until fully combined.
Add Veggies: Stir in the chopped spinach, diced bell pepper, red onion, and cherry tomatoes. Season with salt and pepper to taste. If using cheese, add it now.
Microwave Cooking: Place the mug in the microwave and cook on high for 1 minute. After the minute is up, stir the mixture and return to the microwave for an additional 0.5 minutes, or until the eggs are fully set.
Serve: Once done, carefully remove the mug (it will be hot!). Let it cool for a minute, then enjoy your veggie-packed omelet straight from the mug!
Notes
Customize with your favorite vegetables or cheese.