Preheat the oven to 400ºF. Line a medium baking sheet or use a non-stick sheet. Set aside.
Make the four 'steaks': To make the tofu steaks, turn the block of tofu on its side, with the longer side face up. Slice down the middle lengthwise to make 2 large rectangles. Place both rectangles onto the cutting board, with the larger side face down. Use a sharp knife to cut a crosshatch pattern on the top of both rectangles. Take care not to cut too far down or the steaks will fall apart. Slice each crosshatched rectangle in half lengthwise through the middle to make 4 long, even rectangles. Set aside.
Whisk the marinade: In a medium bowl, whisk the tamari, garlic powder, garlic, sriracha, and black pepper. Add the maple syrup gradually to taste.
Marinate the tofu: Placed the tofu steaks in a rimmed dish in a single layer, crosshatched side face up, and pour about one half of the marinade onto the steaks. Use a pastry brush to coat the steaks generously with the marinade and get it into the cracks. Set aside for at least 15 minutes.
Bake the tofu: Transfer the tofu steaks to the prepared baking sheet. (Pour the remaining marinade back into the bowl.) Bake the steaks for 30 minutes, brushing generously with the marinade every 10 minutes.
Cook the asparagus: Meanwhile, heat the sesame oil in a large non-stick skillet over medium-high heat. Sauté the asparagus for about 5 minutes, or until golden brown and just tender. (For oil-free, brush the asparagus with the marinade and roast with the tofu.)
Heat the sauce: Once the tofu is finished baking, transfer the asparagus to a plate. Add the remaining marinade to the skillet. Heat the marinade over medium-low heat for about 3 minutes, or until it starts to bubble. Pour the marinade over the tofu steaks and asparagus for serving. Serve with the desired grain.