A classic browned butter and sage sauce gets a boost of fall flavor from pumpkin butter. Be generous with the Parmigiano-Reggiano, its salty, savory bite adds the perfect hit of umami flavor to this decadent pasta dish.
In a large, deep skillet of simmering salted water, cook the pasta until al dente. Drain, reserving 1 cup of pasta cooking water.
In a small skillet over medium-high heat, melt the butter. Add the crushed red pepper flakes, minced shallots, sage leaves, salt, and pepper. Whisk until butter begins to bubble and brown. Stir in the pumpkin butter, a splash of pasta water and whisk to combine until saucy. Toss with cooked pasta. Garnish with grated Parmigiano-Reggiano.