Preheat the oven to 400 degrees F. Grease a sheet pan with non-stick cooking spray.
Pat the tofu dry with a towel. Wrap it with a dry towel and place a cast iron pan or cutting board on top to remove more liquid. Let stand for 15 minutes. Cut the tofu into 1-inch cubes.
Arrange the tofu in a single layer across the sheet pan and bake for 10-12 minutes.
While the tofu is in the oven, make the sauce. In a small saucepan over medium heat, combine the soy sauce, 1/4 cup water, maple syrup, rice vinegar, hoison sauce, sesame oil, ginger, garlic and red pepper flakes. Simmer the mixture for a couple minutes until it is fragrant. In a small bowl, stir together the cornstarch and 1 tablespoon water and whisk into the sauce. Continue simmering until the sauce thickens, about 2 minutes.
Flip the tofu to the other side. Add the broccoli and the peppers to the pan between the cubed tofu. Continue cooking for 5 minutes.
Scatter the peanuts across the pan. Cook for an additional 5 minutes until the tofu is lightly browned and the broccoli is tender and bright green, but still crisp.
On the pan, toss the tofu, broccoli and peppers in half the kung pao sauce. Extra sauce can be served on the side or saved for another use.
Sprinkle with scallions. Serve with brown rice.