When tofu spits in the pan and refuses to color, the first thing to inspect is often the surface. Water has to evaporate before the outside can become properly crisp.
Drain firm tofu and pat it dry with a clean cloth or paper towel. Press if your chosen product and recipe benefit from it, but do not crush delicate tofu under a heavy improvised tower. Cut the pieces evenly enough to turn without breaking.
A light starch coating can help, provided the cubes are not already dripping. Shake off excess powder and arrange in a loose layer in the pan. Let one side set before trying to lift it.
The sauce is a separate decision. If you pour it in at the beginning, you are braising the tofu. That may be delicious, but it will not preserve the same dry crust.