8 ounces firm tofu, cut into four 1/2-inch slices 3 tablespoons Thai red curry paste (found in the Asian section of most supermarkets) 3 tablespoons sugar 2 tablespoons fish sauce (or tamari, for vegetarians who don't eat fish) 1/2 pound green beans 1/2 cup vegetable broth 1 tablespoon peanut oil