Preheat your oven to 350 degrees F and have a cast iron or oven-safe skillet ready.
In a large bowl, whisk together the flour, cornmeal, baking powder, baking soda and salt. Add the butter to the bowl, and using your fingers or a pastry cutter work the butter into the dry ingredients until the mixture resembles peas. Mix in the buttermilk until just moistened. Drop the biscuits in 1/4 cup increments into the skillet. Place the pan in the oven and bake for about 15 minutes, or until brown on top and puffed up. Remove from heat.
While your biscuits are baking, prepare your chorizo gravy. To a large nonstick skillet, add the vegetable oil. Heat over medium heat, and add the chorizo sausage. Cook for about 6 minutes, until cooked through. Remove the sausage from the pan with a slotted spoon and transfer to a plate. Leave the burner on.
Add the flour and cook, stirring consistently, for about 5 minutes. Whisk in the milk and continue to whisk until the gravy has thickened substantially, about 8 minutes. Stir in the salt and black pepper and remove from heat. Stir the chorizo back into the gravy and cover until you are ready to serve.
Spoon the gravy over the biscuits and garnish with avocado, cilantro, green onions, and queso fresco. Serve immediately with eggs, bacon and your favorite breakfast foods! Enjoy!