Use a food processor to blend the garlic, Parmesan cheese and roasted walnuts until they are finely chopped.
Add the radish greens couple of handfuls at a time, and blend until chopped.
Add in the honey, lemon juice, and zest and pulse again.
Pour the olive oil slowly into the blender until you reach your desired consistency.
Add salt and pepper to taste.
Store in a jar and add some oil on top to prevent oxidation. The pesto can stay up to one week fresh in the fridge.