If using bulk sausage, crumble into a large skillet over medium-high heat. Cook and stir until evenly browned. Drain grease, and set aside. If using sausage links, cook them until done, then remove and slice into 1/4 inch or so rounds. If using chicken thighs, remove the bone and cut into bite pieces then cook until done. Cook the mushrooms if using those with the meat.

Preheat the oven to 180 C, grease a 9 x 13 inch baking dish with butter or use a non-stick dish.

In a large bowl, stir together the soup, milk, garlic, and pepper. Mix in the sausage or chicken, then add the green beans, and stir until evenly coated. Pour half of the mixture into the prepared baking dish. Top with half of the bread crumbs. Spread remaining green bean mixture over the bread crumbs.

Bake for 30 minutes in the preheated oven. Remove from the oven, and sprinkle the rest of the breadcrumbs over the top. Return to the oven for 5 to 10 more minutes, or until the bread crumbs are toasty, and green beans are cooked to your desired doneness. Let rest 5 minutes before serving.