Pour the browned butter back into the pan and gently heat when your pasta is just moments from done
Add lemon juice, sage leaves, and ½ cup of the pasta cooking water when things are just beginning to sizzle. To emulsify the two liquids together, whisk very fast and forcefully
Then add the pepper.Whisk brown butter mixture rest
To thicken very gradually on a medium or low heat for a minute or two let it bubble very gently
Add to the cooked pasta another ½ cup of pasta water. Toss thoroughly then let it bubble away for thirty seconds or more
Turn the heat down to as low as possible—or off entirely—then evenly cover the top with the grated parmesan. Let it melt on top till it is like this. One to two minutes. If you must assist it along, cover it
Now you are going to grab some tongs and rapidly spin the pasta around and around until the noodles are covered with a glossy even sauce. Taste and adjust the season
You should produce a shiny brown butter lemon sauce at last. The secret is to have the skillet off the heat totally or on the lowest heat level while the cheese melts on top