Begin by peeling and cubing the Yukon Gold potatoes. Place them in a large pot and cover with salted water. Bring the water to a rolling boil over medium-high heat, then reduce to a simmer. Cook the potatoes until fork-tender, about 15-20 minutes. Drain and set aside.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Once hot, add the minced garlic and red pepper flakes. Sauté for about 1 minute until fragrant, stirring frequently.

Add the shrimp to the skillet in a single layer. Cook for 2-3 minutes on each side until pink and opaque. Transfer shrimp to a plate and cover to keep warm.

In the same skillet, add 2 tablespoons of butter and melt over medium heat. Stir in 1 cup of whole milk or heavy cream, bringing it to a gentle simmer. Simmer for about 3-4 minutes until thickened.

Once the sauce has thickened, stir in ½ cup of grated Parmesan cheese until melted. Return the cooked shrimp to the skillet, gently folding them into the sauce.

In the same pot as potatoes, add the remaining 2 tablespoons of butter, ½ cup of whole milk or cream, and season with salt and pepper. Mash until smooth and creamy.

To assemble, place a generous scoop of mashed potatoes on each plate. Top with the creamy garlic shrimp and garnish with parsley and a squeeze of lemon juice.