This recipe yields a large amount and will keep in the refrigerator for up to a month. Use in stir-fries, noodle soups, or anywhere you need an added hit of flavor and heat.
Place red-pepper flakes in a small heat-resistant bowl or pint-size jar. In a small saucepan fitted with a candy thermometer, combine peppercorns, cinnamon, star anise, and oil over medium-low heat. Heat mixture until it registers 325 degrees on the thermometer, 10 to 12 minutes. Turn off heat and let steep 8 to 10 minutes until temperature reaches about 240 degrees. Pour through a strainer into bowl or jar with pepper flakes and let cool completely. Transfer to an airtight container or seal lid if using a jar. The chili oil can be stored in the refrigerator for up to 4 weeks.