Begin by preparing the mashed potatoes. In a large pot, add the cubed potatoes and cover with water. Bring to a boil and cook until tender, about 15-20 minutes. Drain and return to the pot.

Add the milk, sour cream, garlic powder, onion powder, and 2 tablespoons of butter to the potatoes. Mash until smooth and creamy. Season with salt and pepper to taste. Keep warm.

In a large skillet, melt the remaining 2 tablespoons of butter over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant.

Add the shrimp to the skillet and cook for 2-3 minutes on each side until they turn pink and opaque.

Pour in the heavy cream and lemon juice, stirring to combine. Let the mixture simmer for 2-3 minutes until slightly thickened. Season with salt and pepper to taste.

To serve, place a generous scoop of mashed potatoes on each plate and top with the creamy garlic shrimp. Garnish with chopped parsley.