Here is a quick sheet pan dinner for your weeknight rotation--just add rice, if you like. If you can't find baby bok choy, use regular bok choy or a whole head of broccoli, cut into long stalks with florets and trimmed stalks. The teriyaki sauce is a keeper for all kinds of simple vegetable dishes, a poached chicken breast or salmon fillet.
Preheat the oven to 400 degrees F. Spread a sheet pan with 3 tablespoons of the oil.
Arrange the bok choy cut side down on the sheet pan, turning them once to coat lightly with oil.
Put the tapioca into a wide shallow dish. Press each slab of tofu into the tapioca to coat. Arrange the tofu onto the sheet pan. (Reserve the tapioca to thicken the teriyaki sauce.)
Bake the bok choy and tofu until well browned, about 25 minutes. Flip the bok choy and tofu and continue baking while you prepare the teriyaki sauce.
Meanwhile, make the teriyaki sauce by heating the remaining 1 tablespoon oil in a small saucepan over medium heat.
Add the ginger and garlic and cook until fragrant, about 1 minute. Add the soy sauce, mirin, sake, sugar and sriracha, if using. Cook, stirring, until the sugar dissolves.
Add 1 tablespoon of the reserved tapioca (discard the rest) and stir until the sauce thickens and is smooth.
When the bok choy is nicely browned and the tofu is crisp (note that it will not brown very much), remove from the oven. Serve with the sauce drizzled on top and additional on the side.