Heat a large skillet over medium heat. Once hot, add the grape seed oil, garlic, onion, and bell pepper. Season with a pinch each of salt and pepper. Cook for 3–4 minutes, stirring frequently until the onion is translucent and the bell peppers are lightly browned.
Raise the heat to high and add the crumbled tofu. Cook for 5–6 minutes, stirring frequently, to begin browning. Then add the chili powder, cumin, and garlic powder. Stir to coat.
Add the chipotle pepper, adobo sauce (optional), broth, and salsa. Stir to combine, then reduce the heat to low, cover, and simmer for at least 15 minutes. The longer it simmers, the more flavor the tofu will absorb. Stir occasionally.
Prep any desired toppings at this time.
Just before serving, preheat the oven to low broil and position the oven rack at the top of the oven.
Brush the corn tortillas with the grape seed oil and arrange on 1 or 2 baking sheets, making sure they aren’t crowded. Broil for 2–3 minutes on each side, or until light brown and crispy. Watch closely so they do not burn. Set aside.
To serve, top the tostadas with braised tofu and desired toppings. I love avocado, lime juice, hot sauce, cilantro, and red onion.
Braised tofu will keep covered in the refrigerator for up to 5 days, though best when fresh.
You can also enjoy the tofu in burritos, in tacos, or atop salads.