Whisk the soy sauce, maple syrup, rice vinegar, ginger, onion, garlic, and sesame oil together in a small bowl or cup.

Cut the tofu into smaller pieces. This can mean dicing it (1-inch cubes work well), cutting it into triangles, strips or slabs.

Place the tofu into a shallow dish or bowl and pour the marinade over it.

Allow the tofu to marinade for at least 30 minutes or up to 24 hours. Be sure to cover and chill it if marinating for more than 2 hours. Gently stir the tofu periodically while it marinates.

Preheat the oven to 400°F and line a baking sheet with parchment paper.

Arrange the tofu cubes in an even layer on the baking sheet.

Bake the tofu pieces for 30 to 40 minutes, flipping them halfway through and drizzling some excess marinade on top.

The tofu is done baking when the pieces have darkened and shrunk.

Coat the bottom of a medium skillet with oil and place it over medium heat.

When the oil is hot, remove the tofu pieces from the marinade. Gently shake or blot off any excess marinade, then place them in an even layer in the skillet.

Cook the tofu for about 10 minutes, flipping halfway through, until the pieces are browned and crispy.

Drizzle the tofu with some excess marinade and continue cooking until it dries up and caramelizes on the surface of the tofu pieces.

Lightly oil a barbecue grill and build a medium flame.

Remove the tofu pieces from the marinade and place them on the grill.

Close the grill and cook the tofu for about 10 minutes, flipping halfway through, until darkened and lightly charred.