Bring a large pot of water to a boil; salt it, really salt it, use at least 1/4c of sea salt in a 5 qt pot. Cook pasta 2 minutes under lowest time on package. Pasta should be VERY al dente.
Add breadcrumbs and a small amount of olive oil to a skillet. Toast over medium heat until golden brown and set aside.
Melt butter in large skillet or saucepan. Turn heat to medium, and garlic and onion. Saute until translucent and fragrant. Add sage. Cook until butter turns light brown and sage wilts.
Drain the pasta. Immediately add it to the butter-sage mixture, and raise heat to medium. Add 3/4 cup water, and stir; the mixture will be loose. Cook for about 2 minutes, or until some of the water is absorbed and the pasta is perfectly done.
Stir in cheese, and season well with pepper. Add salt to taste.
Top with toasted breadcrumbs, serve.
