Sriracha Blue and Cheddar Gratin of Summer Squash

As the asparagus passes the baton to the summer squash, its getting that time to remember how to cook zucchini and yellow squash in a hundred different ways.  Don't be left empty handed, or you may find yourself up zucchini's creek with no paddle.  And zucchini's make a terrible paddle.
1 yellow squash, sliced
1 zucchini, sliced
½ red onion, sliced

2 oz blue cheese, crumbled
2 oz Cheddar cheese, grated
¼ cup grated Parmesan and/or Romano cheese
Sriracha or other favorite hot sauce
¼ cup Panko bread crumbs

Preheat oven to 400. Lightly oil a 10-inch pie plate or casserole. Layer half the squash and onion on the bottom and sprinkle half of each of the cheeses on top.

Sprinkle with Sriracha to taste. Lightly salt and pepper to taste.
Repeat with the remaining squash, onion and cheese.

Top with the Panko crumbs and bake for about 45 minutes.

Seres 4 as a side dish.

Cook's Note:  I use a fluted slicer that my wife got me as a gift from Pampered Chef one day.  It not only makes things look good, but the ridges it forms seem to separate the slices in the casserole better, making it less dense than with a flat cut with a knife.  A simple gadget with no plug - great stocking stuffer for the chef among you.