In a pot of salted boiling water, cook the pasta until al dente; drain, reserving 3/4 cup of the cooking water. Meanwhile, in a small skillet, heat 1/2 cup of the olive oil until shimmering. Fry the sage leaves over moderate heat, turning occasionally, until crisp. Drain the sage on paper towels, then chop half of the leaves.
Combine the chopped sage, garlic, almond butter, remaining 1/4 cup of oil, scallion, zest, red pepper and all but 2 tablespoons of the cheese. Toss the pasta with the pesto; add the pasta water as necessary to make a creamy sauce. Season with salt and pepper. Top with the remaining cheese and whole sage leaves and serve.