Return skillet to burner, heat remaining ½ teaspoon of oil; add eggs and using a plastic or wooden spatula to push back the eggs that have set, tilt the pan so the uncooked eggs run into the empty portion of the skillet. Continue pushing back cooked eggs and tilting pan until omelet top is wet, but not runny. Turn off heat; working as quickly as possible, sprinkle cheese, mushrooms and thyme down center. Fold ⅓ of the omelet over toppings. Then tilting pan, continue to roll omelet onto plate. Serve immediately.
Recipe by Three Many Cooks at https://threemanycooks.com/recipes/morning-food/omelet-with-mushrooms-and-gruyere/