Dice chorizo and cook in a skillet until crisp at the edges (around 5 mins).
Drain grease from chouriço and pat with paper towel to remove extra grease.
Stir together cream cheese, 4 oz cheddar cheese, and chouriço.
Pack cream cheese mixture into mushroom caps.
Place mushrooms on a baking sheet and sprinkle remaining cheddar cheese over them.
Bake for 7-10 minutes or until cheese is melted and bubbly.
Remove mushrooms from the oven and let them cool on a plate with a paper towel on it (to absorb excess moisture) for approximately 5 minutes before serving.