Place the peanuts in the blender, select MANUAL/LO, and blend. As the peanuts become finer in texture, gradually increase the speed to SPEED 8. Use the tamper as needed to stir the peanut mixture and push it down (the peanuts will move up the sides of the blender as they are processed).
Once the peanut butter is visibly smooth along the sides of the jar and there is a mass of chopped nuts rotating around on the blades, gradually reduce the speed to SPEED 4. Once a vortex forms in the center of the peanut butter, add your mix-ins (if using, see the variations that follow). Once the peanut butter reaches your desired smoothness, stop the blender.
Stir together ½ cup unsweetened cocoa powder and ½ cup turbinado sugar in a small bowl. Once a vortex forms in the center of the peanut butter, add 3 tablespoons peanut oil and the cocoa mixture, ¼ cup at a time.
Once a vortex forms in the center of the peanut butter, add 2 tablespoons ground cinnamon.
Once a vortex forms in the center of the peanut butter, add 2 tablespoons peanut oil and 8 ounces roasted cashews. Continue to blend until the cashews are fully incorporated and the peanut-cashew butter reaches your desired smoothness.
Substitute roasted walnuts for the peanuts. Once a vortex forms in the center of the walnut butter, add 1 tablespoon peanut oil, 3 tablespoons maple syrup, and ½ teaspoon ground cinnamon.
Nut butters made without stabilizers naturally separate. To reincorporate the oil into the nut better, stand the sealed jar or container on its side for a few minutes. The oil will settle on the side, making it easier for you to insert your knife under the butter and give it a stir.