Spray inside of bowl/cup with nonstick spray or lightly coat with butter. Add eggs, salt, pepper, and 1 tablespoon water; whisk with a fork until combined.
Microwave on high 30 seconds; you should see bits of solid egg floating in uncooked part. Stir gently (this will help egg cook evenly) and microwave again 30 seconds or until egg puffs up dramatically. Add cheese and continue to microwave until egg is just set and cheese is melted, 15–30 seconds.
Using a small spatula, transfer egg to bottom bun. Top with avocado, drizzle with hot sauce or pesto, then add top bun.
Recipe adapted from: www.epicurious.com