melt 1/4 c butter in pan, whisk in 1/4 all purpose flour to make roux

cook until thick, set aside to cool

bring milk and onion pique to a simmer for 10 min, be sure not to let milk scald

whisk in roux and continue to simmer. be sure to continue whisking until the roux is fully incorporated into the sauce

once sauce is thickened, pull to side an add salt, pepper and thyme

on med heat, saute onions in butter until partially cooked, add yellow squash

season with s&p, do not overcook veggies, set aside to cool

in large bowl, toss veggies and roux and cheese

place in casserole dish and top with buttered bread crumbs

cover with aluminum

325 for 25-30 min

remove foil and bake till crumbs brown