Toast the Pumpkin Seeds: If your pumpkin seeds aren’t already toasted, spread them in a single layer on a baking sheet and toast in a 350°F (175°C) oven for 5-7 minutes, or until lightly golden and fragrant. Let them cool slightly.
Combine Ingredients: In a food processor, combine the toasted pumpkin seeds, basil leaves, garlic, and Parmesan cheese (if using).
Process: Pulse the ingredients until coarsely chopped.
Add Olive Oil and Lemon Juice: With the food processor running, slowly drizzle in the olive oil and lemon juice until the pesto comes together.
Season: Season with salt and pepper to taste. If the pesto is too thick, add a tablespoon or two of water to thin it out.
Taste and Adjust: Taste the pesto and adjust the seasoning as needed. Add more lemon juice for brightness, salt for flavor, or olive oil for a smoother consistency.
