Zucchini, Squash, and Onion Au Gratin

Vegetables sauteed in butter with cheese.  Yummy.

~ 2 zucchinis, sliced into 1/4 inch pieces
~ 1 yellow squash, sliced into 1/4 inch pieces (Husband likes zucchini better than yellow squash, but feel free to do two of these too :) )
~ yellow onion, thinly sliced
~ 1/2 cup shredded parmesan or aged asiago
~ butter and oo

Saute the vegetables in a little olive oil and a pad of butter, low and slow until very tender.  Make sure they are in an oven safe saute pan (or transfer to one).  Sprinkle the cheese on top and put under the broiler until the top is crispy.

So easy.  So good.