Prepare the potatoes: Wash the potatoes thoroughly under cold running water. Peel them using a vegetable peeler, then cut them into uniform chunks, approximately 5cm (2 inches) in size. Uniformity ensures even cooking.

Boil the potatoes: Place the peeled and cut potatoes in a large pot. Cover them with cold water by about 2.5cm (1 inch). Add about 1 tablespoon (15g) of salt to the water. Bring the water to a rolling boil over high heat. Once boiling, reduce the heat to medium-high to maintain a steady, vigorous simmer. Cook for 15 to 20 minutes, or until the potatoes are fork-tender. You should be able to easily pierce a potato chunk with a fork or knife with no resistance.

Drain the potatoes: Once tender, carefully drain the potatoes using a colander. Shake the colander gently to remove excess water. Return the drained potatoes to the hot, empty pot. Place the pot back on the stove over very low heat for 1-2 minutes, stirring occasionally. This step helps to evaporate any remaining moisture from the potatoes, which is crucial for preventing watery mashed potatoes.

Mash the potatoes: Remove the pot from the heat. Add the unsalted butter (115g or 1/2 cup) to the hot potatoes. Allow the butter to melt for a minute or two. Using a potato masher, begin mashing the potatoes and butter together. Mash until the butter is fully incorporated and the potatoes are starting to break down. For a smoother texture, you can use a ricer or a food mill.

Incorporate wet ingredients: Add the sour cream (240ml or 1 cup) to the mashed potatoes. Stir gently until just combined. If you prefer a thinner consistency, gradually add milk or cream (60ml or 1/4 cup) until the desired texture is reached. Be careful not to overmix, as this can make the potatoes gummy.

Add fresh dill and season: Fold in the finely chopped fresh dill (30g or 1/4 cup). Season generously with salt (approximately 1.5 teaspoons or 8g) and black pepper (approximately 0.5 teaspoon or 2g). Taste and adjust seasoning as needed. Ensure the salt is evenly distributed for the best flavor.

Serve immediately: Transfer the mashed potatoes to a serving bowl. Garnish with a little extra fresh dill if desired. Serve hot as a side dish.