Preheat the oven to 425 degrees F. Cover a baking sheet with parchment paper.
Cut the tofu block in half, lengthwise through the middle, making two blocks about 3/4-inch thick. Then slice the two blocks in half, this time through the center, making 4 triangular pieces of "tofu toast."
Place the tofu in a single layer on the parchment. Spray the top with oil and bake until golden, crispy and slightly bubbling on the top, about 20 minutes.
Take the tofu out of the oven, flip each piece over and spray with oil. Then return to the oven to cook for another 10 minutes. Let it cool slightly, 5 to 10 minutes.
To serve, slather the tofu toast with the avocado and garlic powder. Sprinkle with the black pepper, red pepper flakes and layer on sprouts, radishes and hard-boiled egg if using.
Store any leftover tofu toast in an airtight container, in the refrigerator for up to a week. Reheat in a 400 degree F oven for 5 to 8 minutes, or in a microwave for 1 minute.
Recipe courtesy of Jessica Goldman Foung