In a 9-inch (23 cm) cast iron skillet or oven-safe pan, heat 2 teaspoons of the oil over medium heat. Add the hash browns, pressing gently to flatten them into an even layer. Cook until there is some browning on the first side, about 6 minutes, sprinkling the salt and ⅛ teaspoon pepper over the top while they are cooking. Carefully flip the patty onto a plate and set aside. Preheat the oven to 375oF (190oC, or gas mark 5).
Add the remaining 1 teaspoon oil to the skillet along with the bell peppers and onion, and cook, stirring occasionally, until the onions are nearly translucent, about 5 minutes, then remove from the pan and set aside. While the peppers and onions are cooking, whisk together the chickpea flour, nutritional yeast, cornstarch, kala namak, onion powder, baking powder, and turmeric, if using, in a large bowl. Pour the hot vegetable broth into the chickpea flour mixture and whisk until combined.
Slide the hash brown patty, uncooked side down, back into the skillet, then top with black beans and pepper-onion mixture. Whisk the chickpea mixture to recombine (don’t worry about how thin it is) and pour it over the top. Place the skillet in the oven and bake for 33 to 35 minutes, or until the top is matte and slightly firm.
Remove the skillet from the oven and let cool on a rack for 15 to 20 minutes before serving. If storing for later, wait 30 minutes before cutting the frittata into quarters. Transfer to 4 storage containers and store in the refrigerator for up to 7 days or in the freezer for up to 3 months (allow to defrost completely in the refrigerator before reheating).
Store in the refrigerator for up to 7 days or in the freezer for up to 3 months (allow to defrost completely in the refrigerator before reheating).