Preheat oven to broil on high. Arrange an oven rack 3-inches from the broiler.

Heat olive oil in a large oven-proof skillet over medium heat. Add chorizo or sausage and cook until browned, about 5-8 minutes, making sure to crumble the chorizo or sausage as it cooks. Drain excess fat; transfer to a paper towel-lined plate.

Add garlic, onion and pepper to the skillet. Cook, stirring frequently, until onions have become translucent, about 3-4 minutes.

Whisk in flour until lightly browned, about 1 minute.

Reduce heat to low. Gradually whisk in milk and tomato. Cook, whisking constantly, until thickened, about 4-5 minutes.

Remove from heat. Gradually stir in cheeses until smooth; season with salt and pepper, to taste. Stir in 1/2 the chorizo or sausage and 1/2 cup cilantro.

Place into oven and broil until golden brown, about 2-3 minutes.

Serve immediately with remaining chorizo and cilantro, garnished with pickled jalapeno peppers, if desired.