Heat the oil over medium heat in a medium saucepan. Once hot, add the annatto seeds and fry for 2-3 minutes or until the oil turns orange. Keep an eye on the seeds so they don't burn.
Once the oil has turned orange/red, remove from heat and add the crushed garlic. Let it cool for 15 minutes.
Using a fine-sieve mesh, strain the oil and discard the seeds and garlic. Transfer the oil to a clean glass jar and store it at room temperature for up to 1 month. Use to add color to stir-fries, marinades, curries, etc!