Preheat the oven to 375F. If your pot is not oven-safe, set a 9×9″ baking dish aside.

Warm the oil in a large heavy-bottomed sauté pan or cast-iron skillet over medium high heat. Add the onion along with ½ teaspoon salt and sauté for 3 minutes. Then, add the garlic, cilantro, chili powder, cumin, and oregano to the pan. Sauté for 1 minute, until the garlic is fragrant.

Add the bell pepper, zucchini, and corn to the pan along with the remaining ½ teaspoon of salt. Reduce the heat to medium heat and sauté for 5 to 7 minutes, until the zucchini is translucent and most of the liquid has evaporated.

Add the pinto beans and tomato sauce to the pan and mix well. Bring the dish to simmer and cook for 2 to 3 minutes. If your pan is not microwave safe, transfer the “filling” to a greased casserole dish now. Smooth the top of the filling in either dish and press it down a bit with a spatula.

Combine the masa, water, oil, turmeric, and salt together in a medium bowl and mix well to form a thick, smooth batter. Use a large spoon to dollop the masa on top of the casserole dish, then use a spatula to spread it out into a thin, even layer on top.

Bake in the oven for 25 – 27 minutes, or until the masa is golden and set.

Top as desired and serve warm. Store any leftovers in the fridge for up to 5 days. You can also freeze your leftovers for up to 2 months.