Cut the butter into tablespoon sized pieces and bring to room temperature. Bring a pot of water to a boil and blanch half the ramp leaves for 5 seconds, just until wilted, then refresh in cold water.

Squeeze the leaves dry, then mince fine on a cutting board with the fresh ramp leaves. In the bowl of a food processor pulse the ramp leaf mash to smooth it out a bit, then gradually add half of the butter pieces processing to make a smooth paste (it may take some time if your butter is cold) gradually adding the rest of the butter as you can, continuing to process until the butter is light green and fluffy.

Finally, add the pepper, and drizzle in the lemon juice, processing for a few seconds to lighten it. Spread the butter onto a piece of parchment and refrigerate, or cut into portions and freeze.

The butter will keep for a week in the fridge, and a couple months in the freezer.