Preheat a large cast iron skillet over medium-high heat.

Slice tofu in half crosswise (like if you were to open it like a book) and then in strips. Pat dry on both sides with paper towels then dust generously with cornstarch. Sprinkle one side of the tofu with salt.

Add oil to the pan and when it is shimmering hot, add tofu in a single layer. Cook completely undisturbed (seriously don't budge it!) until it lifts easily and is beautifully golden underneath. Carefully flip all pieces and repeat until golden on the second side. Transfer tofu to a plate and turn off the heat, leaving skillet on the unlit burner.

Whisk sauce ingredients together in a small bowl and add to still-warm skillet. It should bubble up right away and reduce to a thick consistency in just a minute (if not, turn heat back on). Add tofu and turn to coat with the sticky sauce.