Broccoli and Artichoke Bake

2 heads broccoli, cut into florets

2 tablespoons butter

2 cups sliced fresh mushrooms

½ cup chopped green onion

1 (14 ounce) can artichoke hearts, drained and chopped

1 cup sour cream

1 cup mayonnaise

1 cup grated Parmesan cheese

1 tomato, thinly sliced

½ cup dry bread crumbs

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

Bring a large pot of lightly salted water to a boil. Add the broccoli florets, and cook uncovered for a few minutes until the broccoli is just tender. Drain in a colander, then immediately immerse in ice water for several minutes until cold to stop the cooking process. Drain well, place into a large mixing bowl, and set aside.

Meanwhile, melt the butter in a skillet over medium-high heat. Stir in the mushrooms and green onions, and cook until the mushrooms have softened and released their liquid, about 3 minutes. Scrape the mushrooms into the mixing bowl along with the broccoli, then add the artichoke hearts, sour cream, mayonnaise, and Parmesan cheese. Gently fold together until evenly mixed and spread into a 9x13 inch baking dish. Arrange the sliced tomatoes over the broccoli, then sprinkle with the bread crumbs.

Bake in the preheated oven until the casserole is hot and the bread crumbs have turned golden brown, about 25 minutes.