To the pitcher of your blender, add the arugula, basil, garlic, pine nuts, lemon juice and a dash of salt and black pepper. Pulse until the mixture just comes together. With the blender running on low, pour the olive oil in to the pitcher. Continue blending for 3-4 minutes until the pesto is completely pulverized. Adjust seasoning to taste, transfer to an airtight container and place it in the refrigerator where it will keep for about a week.