1. Preheat oven to 400F.
2. Add the butter to a medium skillet or pan over medium heat; once the butter is melted, add the mushrooms and a pinch of salt ad pepper. Cook until softened, but not browned, (roughly 6 to 8 minutes).
3. Add the baby spinach and thyme and cook for a further minute, stirring constantly.
4. Stir in the cream ad halved cherry tomatoes and turn off the heat.
5. Poor the mushroom mixture into individual sized oven-safe gratin dishes and sprinkle cheese on top.
6. Make two wells and crack the eggs into them.
7. Bake until the cheese is melted and the eggs are cooked how you like them (Set whites and runny yolks take about 10 minutes).