Tex-Mex Summer Squash Casserole

Preheat oven to 400°. In a large bowl, combine squash, 3/4 cup cheese, onion, chiles and jalapenos. Sprinkle with flour and salt; toss to combine., Transfer to a greased 13x9-in. baking dish. Bake, covered, until squash is tender, 30-40 minutes., Spoon salsa over top; sprinkle with remaining 1-1/2 cups cheese. Bake, uncovered, until golden brown, 10-15 minutes longer. Let stand 10 minutes. Top with green and red onions before serving.