I have seen this hot oil at a lot of Chinese restaurants, and I found a bag of chili pepper flakes recently, so I thought I would give it a try. At first, I just mixed the oil and pepper flakes, and that did result in hot oil, but it didn't have the same taste or smell as what I was trying for, so I thought about the roasted garlic oil, and I wondered if the results would be better if I roasted the oil. I did that, but the taste and smell were still slightly different from the hot oil I had seen in Chinese restaurants. I'm guessing that the real reason is because I used Korean chili pepper flakes. Even though the smell is a bit different, you can still use the oil in the same way. A little bit goes a long way!