Add the olive oil to a frying pan.
Add the peppers and onions, cook for 3 -4 minutes.
Cook until all vegetables are translucent.
Remove the vegetables to a bowl and set aside
Toast your bun in either a toaster oven or oven at 400 F (Optional)
Watch the bun carefully and remove when lightly browned
Add the egg to the pan
Flip the egg once it is stable, cook just a bit less than your desired done-ness
Test for the desired doneness by pressing on the yolk to feel it. If it is very soft to the touch, you still have a very runny egg, this is not recommended. If your egg has a little firmness but still soft like a marshmallow you have a medium egg. That is how I did mine. If the egg has no softness and is firm, you have a hard egg.
Add the cheese slice in the pan to the top of your cooked egg
As the cheese is melting add the spinach to the pan but do not over cook it. You just want to wilt it.
Place the spinach on top of the egg Carefully remove the cheesy, spinachy egg from the pan and add it to your toasted bun.
Add the onions and peppers on top and the top of the bun