Creme Fraîche Mashed Potatoes with Gruyere

0 Fill a large pot about 3/4 full with water. Stir in about 1 Tbsp of salt (not on ingredients list). Peel the potatoes and slice into even pieces. Add to pot of water.
1 Cover and bring to a boil over medium-high heat. Remove cover and reduce heat to a low simmer. Simmer until potatoes are easily pierced with a fork, 15 to 25 minutes (depending on size of potatoes).
2 Drain potatoes. Cover the colander with a dish towel or lid. Let the potatoes sit in the colander, covered, for 10 minutes (the potatoes will lightly steam; this will draw out the moisture and prevent watery mashed potatoes).
3 Mash potatoes with a masher or by running them through a ricer. (I prefer the ricer for the most light and fluffy potatoes.) 
4 Add melted butter and creme fraîche to potatoes and mash everything together.
5 Heat milk or stock in the microwave or on the stovetop just until warm to the touch. Add to mashed potatoes as needed (start on the low end of the range and add more as needed), until very smooth and creamy. Taste and season with more salt, as needed.
6 Turn on the oven’s broiler.
7 Spray a broiler-safe 3-quart casserole dish with nonstick cooking spray. Spread potatoes evenly into the dish.
8 Sprinkle grated cheese over the potatoes. 
9 Broil potatoes until topping is light golden brown, 3 to 6 minutes.
10 Serve immediately.