Heat the oven: Heat the oven to 425°F with a rack in the center.

Set out a 10-inch oven-safe deep skillet or a 3-quart Dutch oven so you can cook and bake the casserole in the same pan.

Start the vegetables: Put the olive oil in the skillet or Dutch oven and warm it over medium heat.

Add the onion, green bell pepper, scallion whites, and 1/2 teaspoon of the salt to the hot pan.

Cook the vegetables for 5 to 6 minutes, stirring a few times, until the onion looks soft and the pepper has started to lose its raw crunch.

Add the chopped collards to the pan.

Cook the collards for 3 to 4 minutes, stirring often, until they wilt down and turn a darker green.

Stir the smoked paprika into the vegetables and cook for 30 seconds so it smells fragrant.

Cook the grits: Pour the vegetable broth and milk into the pan and raise the heat to medium-high.

Bring the liquid to a gentle boil. You should see steady bubbles around the surface, but it should not boil hard enough to splash.

Slowly sprinkle the quick grits into the pan while whisking so they do not clump.

Lower the heat to medium-low and cook the grits for 4 to 5 minutes, stirring often, until the mixture is thick enough to leave clear lines when you drag a spoon across the bottom.