Thoroughly clean ramps. Separate green leaves from white/ pink roots. Roughly chop.
Place a saute pan over medium high heat, toast the walnuts 3 to 5minutes. Keep a close eye, walnuts go from toasty to burnt quickly. Add toasted walnuts to blender or food processor. Give it a quick whirl to to break up the pieces.
Return pan to stove, reduce heat to medium. Add 1-2 tablespoon of walnut oil to the pan. Add green and white ramp parts, saute 3 to 5 minutes until soften. Move to blender.
Add green ramp leaves, lemon juice, cheese, and pinch of salt to blender. Pulse to combine. Slowly add the walnut oil while blending on high speed. Start with a ⅓ cup of walnut oil and add more, if needed, to get to desired consistency.
Adjust salt, pepper and lemon juice to taste.
It is optional to blanch the green ramp leaves. I only do this if I am making the pesto ahead of time and want to ensure it stays vibrant green.
Sauteeing the wild ramps is an optional step but I find it brings out a bit of the natural sweetness.