This is a variation on my mother-in-law's Cheesy Summer Squash Saute, which is also delicious.
2 medium summer squashes or zucchinis, sliced in 1/4-inch rounds
1 large onion, chopped or in long slices
2-3 Tbsp finely chopped fresh sage leaves
Salt and pepper to taste
3-4 Tbsp grated Parmesan
Heat some olive oil in a large skillet. Add the onion and squash or zucchini and saute, stirring occasionally, over low-medium heat for several minutes until tender and lightly browned in places. Add the sage, salt, and pepper and stir. Sprinkle the Parmesan over the vegetables, turn off the heat, and cover for a few minutes. Serve once the cheese is melted.
Serves about 4.