Melt the butter into a small saucepan over medium heat. Once melted and frothy add the minced onion and cook, stirring occasionally, for 7-8 minutes until golden brown and very soft. Add the garlic and sauté for 1 minute more.
Add the huitlacoche and stir to combine. Season with epazote, oregano, cumin, lemon juice, and salt, pepper, and crushed red pepper. Bring to a low boil, reduce heat, and simmer for 15 minutes.
After 15 minutes, stir in the water and taste and season to your preferences. Purée with an immersion blender until smooth. Set aside and keep warm.
Char the Vegetables:
Turn the broiler on. Heat 1 teaspoon oil in a skillet over high heat. Add the onion and peppers and cook without moving for 2-3 minutes until the onions begin to char around the edges.
Add the cherry tomatoes and season everything with salt and pepper. Add another drizzle of oil on top of the tomatoes and transfer to the broiler for 4-5 minutes until the vegetables are all soft and the cherry tomatoes begin to blister and char. Return the skillet to the stove and transfer the vegetables to a bowl and keep warm. Carefully wipe out the pan.
Sear the Scallops:
Pat the scallops dry sprinkle with salt and pepper.
In the skillet, heat another drizzle of oil over high heat until very hot and shimmering.
Add the scallops in an even layer and cook without moving until very well-seared and dark brown. Flip and cook until the scallops are opaque and cooked through, but not overcooked. Total cooking time will be about 3 minutes, with most of the cooking time happening on the first side of the scallops.
Transfer the cooked scallops to a plate.
To Serve:
Dress the greens with a touch of extra virgin olive oil and sprinkle with salt and pepper. Spoon a tablespoon or two of the huitlacoche sauce on both plates and use the back of your spoon to spread it around half the plate. Arrange the greens next to the sauce on both plates and pile the charred vegetables on top. Arrange the cooked scallops on top and serve immediately. Enjoy!