2 pounds (about 3 large) russet potatoes, peeled and grated
1 small to medium onion, finely diced
3/4 teaspoon salt
3/4 teaspoon freshly ground black pepper or more to taste
1 cup creme fraîche
1/2 cup half-and-half
3 large eggs
1 to 2 tablespoons minced fresh chives
1/4 teaspoon dry mustard
1 cup grated pepper jack or sharp Cheddar cheese (about 1/4 pound)
Heat oven to 375 degrees F.
Warm oil in a heavy, ovenproof 8- to 9-inch skillet over medium
Add potatoes and onion, stir to coat with oil, sprinkle in
at least 1/2 teaspoon each salt and pepper, and pat mixture down.
Par-cook potatoes, scraping up and patting back down several times,
until golden, somewhat sticky, crispy in spots, and reduced in volume
by about half, about 15 minutes.
Remove from heat. Press potato
mixture down around bottom and up edge of skillet to form a crust
about 1 1/2 inches high. A spoon helps in shaping it evenly.
Whisk together creme fraîche, half-and-half, eggs, chives, dry mustard
and 1/4 teaspoon each of salt and pepper.
Sprinkle cheese into potato crust, then pour creme fraîche mixture
Dust with paprika.
Bake for 25 to 35 minutes, until puffed
and lightly browned and a small thin knife inserted in center comes
Let sit at least 10 minutes to firm a bit before slicing.