How to Make It
Heat a large skillet over medium heat. Add 1 tablespoon oil to pan; swirl to coat. Add onions; cook 16 minutes or until golden, stirring occasionally. Remove pan from heat.
Place potatoes in a large saucepan; cover with water to 2 inches above potatoes. Bring to a boil. Reduce heat, and simmer 14 minutes or until potatoes are tender. Drain. Return potatoes to pan; mash to desired consistency.
Combine remaining 4 tablespoons oil and garlic in a small skillet; heat over medium-low heat 5 minutes or until garlic is lightly golden. Remove pan from heat; cool 3 minutes. Mash garlic into a paste with the back of a fork. Stir onion mixture, garlic mixture, milk, salt, and pepper into potato mixture. Return pan to medium heat; cook 3 minutes or until thoroughly heated.