Cover cutting board with piece of plastic wrap and place tofu halves side-by-side on top of plastic. Cover with second piece of plastic, then second cutting board. Weight down with large cans of tomatoes or a cast-iron skillet. Let stand 1 hour to compact texture and press out water.
Preheat oven to 350°F. In small saucepan, boil broth until reduced by half, about 15 minutes. Remove from heat and stir in soy sauce, oil, vinegar, ginger and garlic.
Arrange pressed tofu to cover bottom of 9 x 5-inch loaf pan; pour warm broth mixture on top. Bake, uncovered, 45 minutes to 1 hour. Transfer pan to a wire rack and cool completely in liquid.
With slotted spatula, transfer tofu to plastic container; discard liquid. Cover and refrigerate thoroughly to firm texture, at least 4 hours or overnight.
To serve, thinly slice tofu lengthwise, holding knife at 45° angle. Place tofu slices in large saucepan, add gravy and warm through over low heat. Place slice of toast on each plate. Arrange several tofu slices on top; spoon gravy over. Serve hot, with mashed potatoes and cranberry sauce if desired.