Step 1Melt the butter in a small saucepan and add the parsley and a few drops of lemon juice. Beat the egg in a large bowl.
Step 2Bring a large pot of abundantly salted water to a vigorous boil and add the pasta and kohlrabi leaves. Cook the pasta until al dente, 4 to 5 minutes and drain well. Toss the pasta and kohlrabi leaves with the butter, cheese, egg, and pepper to taste. Serve immediately.