This basic tofu is delicious alone and with the miso sauce. But you have a host of other options as well: you can smother it with sautéed mushrooms or onions, you can put it in a sandwich with the works, or you can even slice it thinly then toss it with skinny udon noodles and peanut sauce. There are endless possibilities.
Drain the tofu then slice it crosswise into 6 pieces. Heat a cast iron or non-stick skillet. Add the tofu, sprinkle with salt and pepper, and cook over medium-high heat until golden. At first it will twitch around as the water in the tofu turns to steam, but then it will settle down. (Note: Tofu has fat in it so it will brown without adding more oil.) Once the first side is browned, turn and cook the second side, around 10 minutes in all. Shake over a tablespoon or two of your sauce of choice (soy, tamari, Worcestershire), season with salt and pepper to taste, and immediately turn off the heat. You can move to Step 2 while the tofu cooks.
For The Miso Sauce
While the tofu is cooking, using a small saucepan, mix the miso with the sugar and lemon juice. Cook over low heat and cook while stirring until the sugar is dissolved and the mixture is bubbly, about a minute. Let it cook, then stir in the lemon zest and vinegar. Taste to make sure the mixture has enough lemon (if using Meyer lemon, you might want to add a little more juice).
Place the tofu on a plate. Spoon the sauce over the finished tofu and garnish with the scallions and sesame seeds.