Place the peeled and chunked Russet potatoes into a large pot. Cover the potatoes with cold water by at least 2.5cm (1 inch). Add 1 teaspoon (6g) of the salt to the water.

Bring the pot of potatoes to a boil over high heat. Once boiling, reduce the heat to medium-high and simmer, uncovered, for 15-20 minutes, or until the potatoes are fork-tender. They should be very easily pierced with a fork or knife with no resistance.

While the potatoes are boiling, gently warm the heavy cream in a small saucepan over low heat or in the microwave. Do not boil the cream. Warm cream incorporates better into the potatoes.

Once the potatoes are tender, carefully drain them in a colander. Allow the potatoes to sit in the colander for 2-3 minutes to let excess steam escape. This step is crucial for achieving fluffy mashed potatoes and preventing a watery consistency.

Return the drained potatoes to the empty pot. Add the unsalted butter (115g or 1/2 cup), the warmed heavy cream (240ml or 1 cup), the grated Parmesan cheese (100g or 1 cup), the remaining 1/2 teaspoon (3g) salt, the black pepper (1/2 tsp or 2.5g), and the garlic powder (1/4 tsp or 1g).

Using a potato masher or a sturdy fork, begin mashing the potatoes. Mash until they reach your desired consistency. For extra smooth and creamy mashed potatoes, you can use a potato ricer or a hand mixer on low speed.

Continue mashing and stirring until the butter has melted, the cream and Parmesan cheese are fully incorporated, and the mixture is smooth and creamy. Taste and adjust seasoning with more salt and pepper if needed.

Serve the creamy Parmesan mashed potatoes immediately. Garnish with extra Parmesan cheese and a sprinkle of fresh parsley, if desired.