Dry fresh fir needles out of direct sunlight for 1–2 days. Blend the needles and olive oil on medium high in a blender or food processor for 4 minutes. Pour the mix into a stainless steel bowl. Meanwhile, boil a pot of water, then turn off the heat before floating the bowl in the water for 30 minutes. After this warm infusion, remove the bowl from the water, cover the top with a paper towel, and let sit overnight. Strain through a coffee filter or paper towel and transfer the infused oil to a clean jar. Let it sit covered overnight to allow any residual water and debris from the needles to settle to the bottom. Carefully decant the oil or use a small baster to transfer it to a clean jar or glass bottle; don’t transfer any sediment. The oil is now ready to use and should smell pleasantly of fir and olive oil. Any off odors or excess cloudiness indicates spoilage.

If not using within two weeks, store the oil in the fridge, where it should last for a few months. To use, set it out of the refrigerator ahead of time to allow the solidified oil to liquify.