Fresh rye fettuccine with cultured butter

Whisk four cups of heavy cream with half a cup of cultured buttermilk, cover and leave at room temperature for 24 hours until thickened into creme fraiche.

Whip the creme fraiche with an equal part of room-temperature European butter until the fat separates from the new buttermilk, about 15 seconds.

Wash the butter in ice water four or five times until the water squeezed out runs clear; squeeze out the water and refrigerate.

Make an egg pasta from about 80% 00 flour and 20% rye flour (about 16 oz total), two teaspoons of kosher salt and three large eggs, beaten into the flour with a fork.

Knead 8 to 10 minutes, then wrap and rest 30 minutes before rolling.

Roll out, fold in thirds and roll again three to four times, then roll thinner to the desired thickness and cut into fettuccine; drape into nests on a floured baking sheet, cover and refrigerate.

Cook in a small amount of boiling water for about a minute and a half while a saute pan is kept warm, not hot.

Combine the pasta, cultured butter, a little pasta water and kosher salt in the warm pan and toss vigorously to aerate and emulsify the sauce.

Twist into a nest on a warm plate; top with a dollop of creme fraiche, shaved fresh brewer's yeast and black pepper.