Start by peeling and cubing your Yukon Gold or Russet potatoes. Place them in a large pot of salted water, bringing it to a boil over medium-high heat. Let them cook for about 15 minutes, or until fork-tender. Drain the potatoes and return them to the pot while you prepare the creamy garlic shrimp.

Add butter and warmed milk to the drained potatoes in the pot. Mash everything together until you achieve a smooth and creamy texture. Season with salt to taste, then cover the pot with a lid to keep the mashed potatoes warm while you move on to the shrimp preparation.

In a medium bowl, toss the peeled and deveined shrimp with olive oil, paprika, garlic powder, salt, and pepper. Heat a skillet over medium-high heat, then add the seasoned shrimp in a single layer. Sear them for 2-3 minutes on each side, until they turn pink and opaque. Gently transfer the cooked shrimp to a plate and set aside.

In the same skillet, reduce the heat to medium and add a bit of butter. Once melted, sauté minced garlic for about 1 minute until fragrant. Pour in heavy cream, stirring gently and bringing it to a simmer. Then, add in the Parmesan cheese and Dijon mustard, if using, stirring until combined and slightly thickened, which should take about 3-5 minutes.

Return the cooked shrimp to the skillet with the creamy garlic sauce. Let them simmer lightly for an additional minute to soak up the flavors. Ensure everything is heated through and the sauce has reached the desired consistency, allowing the shrimp to steadily meld with the creamy garlic sauce.

To plate your dish, spoon a generous serving of the buttery mashed potatoes onto each plate. Top with the succulent shrimp and pour the creamy garlic sauce over everything. Garnish with fresh thyme for added color and flavor. Serve immediately and relish in your deliciously comforting Creamy Garlic Shrimp Over Mashed Potatoes!