Boil the potatoes in salted water until tender, about 15-20 minutes.
Drain the potatoes and mash them with milk and butter until smooth. Season with salt and pepper.
In a skillet, heat olive oil and butter over medium heat.
Add minced garlic and sauté until fragrant, about 1 minute.
Add the shrimp to the skillet and cook until pink and opaque, about 3-4 minutes.
Pour in the heavy cream and stir to combine. Let it simmer for a few minutes until slightly thickened.
Season the shrimp mixture with salt, pepper, and chopped parsley.
Serve the creamy garlic shrimp over the mashed potatoes.