Pour 1 quart of neutral oil into a pot along with the garlic and spices (coriander seeds, star anise, cinnamon sticks, Sichuan peppercorns).
Gently simmer the oil and spices for 1-2 hours, maintaining a temperature between 230°F to 250°F.
In a large metal bowl, combine 1 cup of Asian red pepper flakes (or regular red pepper flakes), ¼ cup dried onion flakes, 1.5 tsp salt, and 1 Tbsp black vinegar (or balsamic vinegar).
Slowly pour the hot oil over the chili mix, making sure to cover all the ingredients.
Allow the mixture to cool completely.
Add 2 Tbsp sesame seeds and 1 Tbsp sesame oil to the cooled chili oil.