Preheat toaster oven to roast garlic (if not already roasted).

Peel and cube the potatoes.

Place potatoes in a large pot, cover with water, and salt the water.

Bring water to a boil on high heat.

Boil potatoes until fork tender.

While potatoes are cooking, dice the onion, roasted garlic, and chorizo.

Heat olive oil in a large skillet over medium heat.

Sauté onions until semi-translucent.

Add chorizo to the skillet with the onions.

Cook until onions are brownish and the chorizo is crisp.

Add diced roasted garlic (optional).

Drain cooked potatoes and transfer to a bowl.

Add butter and 1/4 cup of milk.

Use a hand mixer to blend potatoes until smooth.

Add remaining 1/4 cup of milk (if needed) to adjust consistency.

Add chorizo, onions, and roasted garlic to the mashed potatoes.

Mix well and serve.