Begin by peeling about 2 pounds of Yukon Gold potatoes and cutting them into evenly sized chunks, around 1-2 inches.

Transfer the potato chunks to a large pot and fill it with cold, salted water until the potatoes are submerged. Bring the water to a boil over medium-high heat, then reduce to a simmer, cooking the potatoes for about 15-20 minutes.

Once the potatoes are fork-tender, carefully drain them in a colander. Allow them to steam for a few minutes back in the pot.

In the now-empty pot, add the drained potatoes back in. Mash the potatoes until smooth and fluffy. Then, mix in Boursin cheese, unsalted butter, sour cream, and warm whole milk.

Evaluate the texture of your mashed potatoes. If they feel too thick, gradually add more warm milk.

Before serving, taste your mashed potatoes and adjust the seasoning with salt and pepper. Serve hot, garnished with freshly chopped herbs.