If you use raw "Ají Amarillo" or other Chili, remove seeds and veins, then cook in a water and after 8 min, drain the "ajies" and fill again with water, then cook it for another 8 minutes, if you do not know how spicy is your chili/aji, you should repeat the process at least 4 times (just to make sure the chili is not spicy at all) if you like it a little spicy 2 to 3 times is fine
Chop your onions, crush your garlic and in a pot add oil, Onions, garlic, "Ají Amarillo paste"
Let it cook on medium/high heat until tender, what we are looking here is to caramelize the onions and to cook all the ingredients.
Once your ingredients are cooked, blend all the mix with the cheese, milk, and crackers add salt and pepper if necessary.