Mexican Casserole

poblano chiles

large red bell peppers

frozen corn, thawed

all-purpose flour

salt, divided use

freshly ground black pepper

2% milk, or your choice

vegetable broth

shredded Mexican blend cheese, divided use

finely chopped red onion

chopped fresh cilantro

large eggs, lightly beaten

carton part-skim ricotta cheese

white beans, drained and rinsed

6-inch white corn tortillas

thinly sliced green onions, divided use