Note: You can even make a double batch and freeze some for later!
Using your food processor, add the peas and garlic, lemon juice, basil, salt and pepper then pulse together. If you are going to add in parmesan cheese do it now (it will taste fine without it but I am Italian).
While the machine is running, slowly add the olive oil. This will take about 1 to 2 minutes. Take mixture out of the food processor and transfer to a bowl or container.