Begin by heating the extra virgin olive oil in a large skillet over medium heat. Once the oil is shimmering, add the diced red onion. Sauté for about 2-3 minutes until the onion becomes translucent and fragrant.
Next, toss in the mixed mushroom slices, zucchini, yellow squash, and red bell pepper. Stir occasionally, cooking for about 5-7 minutes, or until the vegetables are tender but still vibrant.
Sprinkle in the kosher salt, black pepper, chili powder, cumin, dried oregano, and crushed red pepper. Stir well to coat the vegetables evenly with the spices, allowing them to cook for another 1-2 minutes.
Add the drained and rinsed black beans to the skillet along with the salsa. Stir everything together and let it simmer for about 5 minutes, allowing the flavors to meld beautifully.
Reduce the heat to low and sprinkle the shredded cheddar cheese evenly over the mixture. Cover the skillet with a lid for a few minutes, allowing the cheese to melt into a gooey, delicious topping.
Once the cheese is melted and bubbly, remove the skillet from the heat. Gently fold in the diced tomatoes and sliced green onions for a fresh finish. Serve the cheesy mixture in taco shells or on a bed of greens for a delightful twist.
