Scoop out the stalks and insides of the mushrooms, leaving the caps in tact. Chop the stalks and insides, then combine with the chorizo in a frying pan over medium high heat. Fry gently till browned, then remove from heat.
Combine the chorizo and mushroom mixture with all remaining stuffing ingredients, and mix well. Fill the mushroom caps with the mixture, then drizzle with olive oil and top with breadcrumbs. Place the mushrooms on a parchment-lined baking tray.
Bake for 10 minutes in a 190 C / Gas 5 oven, or until cheese has melted and the mushroom caps are tender.
If not enough mixture as depending on size of mushrooms make more, enjoy!