Separate the white bulb and green stalk of the green garlic. Rinse very well and finely chop the white bulb up like you would an onion, and roughly chop the green stalks.
Bring the stock to a boil, and blanch the green parts until tender (about 3 minutes). Add the spinach or arugula for the last 30 seconds, then remove with a spider or slotted spoon and place in an ice bath to stop the cooking and preserve the vibrant green color. Drain the water from the greens and and purée in a blender until smooth. Use the blender's tamper or a spatula (when the blender is off) to move the greens towards the blade. Add a little cold water to the greens to help get an even purée.
Heat a few tablespoons of olive oil in a medium-large sauce pan over medium heat. Add the chopped white parts of the green garlic and season with salt. Stir frequently and sautée until tender.
Add the arborio rice, season with more salt and stir. Cook for a few minutes to toast the rice.
Pour in the white wine and stir until it is absorbed. Increase the heat and gradually add the simmering stock ½ cup at a time until it is absorbed, stirring frequently until the rice is cooked al dente.
Once the rice is cooked, stir in the green garlic puree and the butter. Remove from heat and stir in the parmesan cheese. Season with salt and freshly ground pepper.
Garnish with a drizzle of good extra virgin olive oil and parmesan crisps.