Saute mushrooms and sliced leeks with butter, garlic, and oregano for 5-10 minutes. Spread vegetables on a baking sheet lined with parchment paper and olive oil. Bake at 400 deg for 10-12 minutes. Remove baking sheet, crack a few eggs overtop and then bake for another 10 minutes, until egg whites are set and yolks are runny. Garnish with fresh thyme.