Thoroughly wash carrot tops in cold water to remove all grit, then pat dry with a kitchen towel.

Place the carrot tops, garlic cloves, and toasted walnuts into a food processor.

Pulse the mixture until the ingredients are finely chopped and combined.

Add the grated Parmesan cheese and lemon juice to the food processor.

With the motor running on low, slowly drizzle in the extra-virgin olive oil until the pesto reaches a smooth, emulsified consistency.

Season with salt and pepper to taste and pulse once more to incorporate.

Transfer to a clean container and serve immediately or store with a thin layer of olive oil on top to prevent oxidation.