You can indeed. The reason they use pine nuts or walnuts is because of the slightly creamy texture of the nuts. Pine nuts, look like puffed rice and give a nice flavor and creamy texture. Typically they are added raw, but I like to toast mine slightly. You can use almonds or peanuts if you prefer that flavor. I would consider food processing them first, then add the cheese, garlic and then some olive oil. Then add the basil and olive oil to finish. You cannot use too much olive oil, I use a good one because you're not cooking with it. That way you dont over process the basil when you are trying to break down the firmer almonds or peanuts. I wold consider using raw almonds, or perhas slightly toasted ones. And no dry roasted peanuts, and without the brown skins. Costco has a large can of cooked and salted peanuts. You need to control the salt. If the salt is too much from those peanuts, you can rinse them in a sieve then pat them dry, then go tot town. There are many forms of pesto, I have seen recipes using wild garlic leaves, and other items. So play with it till you find what works for you and enjoy!