Roasted Mushroom and Green Bean Casserole

or french green beans, trimmed and cut into 1-inch pieces

or cremini, oyster or other mushroom, cut into bite-size pieces

large, halved lengthwise and thinly sliced into half-moons

minced

or half-and-half

or 1/2 bouillon cube

shredded, or grated

store-bought, or homemade, or onions