Here’s a hearty, vegetable gratin with a crunchy, cheesy topping. A gratin is a dish that has a cheese and breadcrumb crust. This is a one-pot vegetarian meal that can be made ahead and rewarmed. You can add any type of vegetables you have on hand and use this recipe as a guide for the amounts. Helpful Hints: — You can use any type of mushrooms. — You can use pecans or almonds instead of walnuts. Countdown: — Prepare ingredients. — Preheat broiler. — Make the gratin. Shopping List: To buy: 1/4 pound cauliflower florets, 1/4 pound broccoli florets, 1/4 pound sliced portobello mushrooms, 1 bottl…