Peel and cut Potato (2 pound) into 1-inch cubes.
In a pot of cold water, add in the potatoes and bring to a boil. Cook until a fork can easily pierce through, about 15 minutes. Drain and set aside.
Place drained potatoes in the same pot and add Butter (4 tablespoon) and Milk (3/4 cup). Using a potato masher, slowly incorporate potato mash into the milk. Mash until smooth and creamy. Season with Salt (to taste) and Ground Black Pepper (to taste).
Thinly slice Button Mushroom (0.5 pound). Destem Kale (2 bunch) and roughly chop into bite-size pieces. Mince Garlic (5 clove).
In a frying pan, add Olive Oil (1 tablespoon) and garlic, cook until garlic starts to sizzle over medium-high heat.
Add in Shrimp (2 pound) and Paprika (1 teaspoon), cook until just opaque, about 2 minutes. Season with Salt (to taste), remove from the pan, and set aside.
In the same pan, add more Olive Oil (1 tablespoon) and add in the mushrooms. Season with a pinch of Salt (to taste) and cook until all the moisture from the mushroom is almost gone, about 10 minutes, stirring occasionally.
When the mushrooms start to turn slightly brown, add in kale handful by handful, stir and cook them until slightly wilted.
Add the shrimp back to the pan, season the dish with Salt (to taste) and Ground Black Pepper (to taste), mix well, and cook for another minute.
Serve the kale mushroom shrimp with mashed potatoes.