For the Sauce: cut the butter into small pats. Add to a skillet and melt over medium heat. Once the butter becomes foamy, add the fresh sage leaves. Continue to cook, stirring gently with a spoon, until the spotty white milk solids subside and the sauce becomes “honey” golden in color (not yet brown). Note: this sauce will change from golden to brown butter in a nano second- do not walk away from the pan! If using lemon, squeeze some in at the end. 

To Serve with Pasta: while the pasta cooks, make the sauce (you’ll need a large 12-inch skillet). Using tongs, transfer the pasta into the pan, allowing some of the water to still cling to the pasta. Grate fresh Parmesan cheese on top. Toss the pasta with the sauce, adding more pasta cooking water, as needed, to emulsify the texture. Serve immediately with the crispy sage leaves scattered on top.

To Store: this sauce is best made and served fresh. However, you can any store any leftovers in an airtight container. Chill for 3 days or freeze for up to 1 month. Defrost at room temperature. Re-heat to serve.