Heat a medium nonstick skillet over medium-high heat. Add oil to pan; swirl to coat.
Add shallots, garlic, mushrooms, and thyme; sauté 7 minutes or until mushrooms are browned. Add spinach; sauté 4 minutes or until liquid almost evaporates.
Remove mixture from pan; discard thyme sprig. Wipe pan clean.
Combine 1/4 teaspoon salt, 1/8 teaspoon pepper, and 4 eggs in a small bowl, stirring with a whisk.
Return pan to medium heat. Add 1 1/2 teaspoons butter; swirl to coat.
Add egg mixture; cook 1 minute. Lift edges of omelet with a rubber spatula, tilting pan to roll uncooked egg onto the bottom of the pan.
Cook 1 minute or until the center just begins to set but is still very soft. Arrange half of te mushroom mixture over middle of omelet; sprinkle with 1/4 teaspoon salt and 1/8 teaspoon pepper.
Run a spatula around edges and under the omelet to loosen from the pan; fold in half. Slide omelet onto a plate. Repeat procedure with remaining ingredients. Cut omelets in half and enjoy.
Serving Size 1
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.