Asparagus and Mushroom Casserole

1 pound fresh asparagus, trimmed and cut into 1 1/2-inch pieces

1 tablespoon olive oil

1 (8 ounce) package sliced fresh mushrooms

¼ onion, thinly sliced

1 (4 ounce) packet saltine crackers, crushed

1 cup shredded sharp Cheddar cheese

¼ teaspoon ground black pepper

1 (10.75 ounce) can condensed cream of mushroom soup

½ cup milk

½ cup coarsely chopped pecans

Preheat oven to 350 degrees F (175 degrees C).

Grease a 1 1/2-quart baking dish.

Place a steamer insert into a saucepan and fill with water to just below the bottom of the steamer. Cover pan and bring the water to a boil. Add asparagus, cover, and steam until just tender, 5 to 8 minutes.

Heat olive oil in a large skillet; cook and stir mushrooms and onion until the mushrooms have given off their liquid, 5 to 8 minutes. Stir in the asparagus, tossing vegetables just until hot. Remove from heat.

Mix saltine cracker crumbs, sharp Cheddar cheese, and black pepper together in a bowl; spread half the mixture into the bottom of the prepared baking dish.

Spoon the asparagus mixture over the crumb mixture.

Whisk the cream of mushroom soup and milk together in a bowl until smooth, and pour the soup mixture over the asparagus mixture.

Spread the remaining crumb-cheese mixture over the casserole and sprinkle with pecans.

Bake in the preheated oven until the casserole is bubbling, about 30 minutes.