Mix the oil, brown sugar and honey together in saucepan. Warm the ingredients over low heat, stirring frequently, until it is syrupy. Do not let it boil. Remove from heat. Add the vanilla.
Pour the syrup over the oats and stir to combine. Add in the nuts and pour the mixture into a large 10" x 15" glass baking dish sprayed with nonstick spray.
Bake at 350 degrees for 30 minutes, stirring every 10 minutes. Be sure to stir the granola on the edges toward the center so it doesn't over-brown.
After taking the granola out of the oven, stir it a couple of times as it cools. Store it in an airtight container.
You can add other things besides nuts. I often add coconut or chia seeds. I add in dried fruit after the granola is baked.