Blend oil and basil leaves in a blender or food processor for 30-60 seconds, just until the two are mix. Pour mixture into a small saucepan and heat over medium heat, just until bubbles appear around the edges. Heat for about 5 minutes, the remove from heat and let cool completely. Once cool, pour through a fine mesh strainer and press on the basil leaves to release all the oil. Store in an airtight container for 2-3 weeks – stays fresh best if set in the fridge.