1. Blanch
green beans
in boiling water for 3 minutes, then drain 2. Add
butter
to now-empty saucepan and melt over medium-high heat 3. Add
mushrooms
,
garlic
, 3/4 teaspoon salt, and 1/8 teaspoon pepper; cook until mushrooms release moisture and liquid evaporates, about 6 minutes 4. Add
flour
and cook for 1 minute, stirring constantly 5. Stir in
chicken broth
and bring to simmer, stirring constantly 6. Add
cream
, reduce heat to medium, and simmer until sauce is thickened and reduced to 3 1/2 cups, about 12 minutes 7. Season with salt and pepper to taste 8. Add blanched
green beans
to sauce and stir until evenly coated 9. Arrange in even layer in
baking dish
; sprinkle with
green bean casserole mix
10. Bake until top is golden brown and sauce is bubbling around edges, about 15 minutes. Serve immediately. ```