Mince your onion and shallot. I used my mini-prep to mince mine, so don't feel you have to use a knife.
Add the onion and the shallot to a medium-large pot and cover with COLD oil. Turn the heat on medium and let the oil slowly come up to temperature. Watch carefully and stir every few mins to make sure the shallot and onion brown evenly.
2 cups Neutral oil, 10 cloves Garlic, 1 large Shallot
While the onion and the shallot are infusing, in a LARGE heat-safe bowl, stir together the gochugaru, chili flakes, grated ginger, sugar, and sesame seeds. (This is also where the mushroom powder and MSG would go if you are using them.) You want a bowl significantly larger than you think you need because you're going to pour the hot oil in this bowl and it will bubble and sizzle.
2/3 cup Gochugaru or ground Korean chilies, 2/3 cup Chili flakes, 2" piece Fresh ginger, 2 tbsp Sugar, 2 tsp mushroom powder, 2 tsp MSG powder, 2 tbsp Sesame seeds
Once the garlic and the shallots go light golden brown, strain them out of the oil and reserve the oil. Either pour through a strainer/sieve or lift them out with a fine mesh spider. They will keep cooking for a bit after coming out of the hot oil, so don't wait for them to get deep brown. Spread them out on a napkin or plate and let them crisp up. Return the strained oil to the pot and bring it up to 350°F. Use a thermometer for this. Burnt oil makes for sad, bitter chili crisp.
Pour the hot oil slowly over the spice mixture, stirring carefully. It will bubble and froth and spit. This is why you used the LARGE metal bowl. Give it a good stir and let it sit for at least 5 mins.
Stir in the soy sauce and rice vinegar.
2 tbsp Rice vinegar, 2 tbsp Soy sauce
Let the mixture cool - not to room temp but cool enough that you can touch it - and add the browned garlic and ginger bits back into the mixture.
Spoon it into a jar and keep it in the fridge.