Cut the tofu into 1 inch cubes, top with a layer of paper towels, then cover with a layer of heavy objects like cast iron skillets topped with canned goods. Let it sit for an hour to release a lot of its moisture.
Meanwhile, preheat the oven to 425 F.
Remove the weights and discard the paper towel.
In a small bowl, mix together the panko, sesame seeds, and Chinese five spice.
Brush the tofu in the mustard, then toss in the mixture. Season with a generous pinch of salt and pepper. Transfer to a baking sheet and bake for 30-40 minutes, flipping at least once throughout the cooking process.