Heat olive oil in a skillet over medium heat until it shimmers lightly

Crack the egg into the pan and cook until the whites are set and the yolk reaches your preferred doneness

Sprinkle the egg with a pinch of salt while it cooks to enhance flavor

In a small bowl, toss the microgreens with lemon juice, lemon zest, and red pepper flakes until lightly coated

Spread pesto evenly over both halves of the toasted muffin

Layer avocado slices on one half, pressing gently so they stay in place

Place the warm egg on top of the avocado, allowing the heat to soften it slightly

Add the dressed microgreens on top for a fresh, slightly tangy crunch

Close the sandwich with the top muffin half and serve immediately while warm