Deep-frying is the process where food is immersed in hot oil or fat to be cooked. You can make chops this way, or fried potato and so on. Food can be partly cooked in advance and then finished just before being served.
To partially cook food you immerse it in the preheated (to 160C-175C) fat or oil until softened and not coloured.
To fully cook food you immerse it in the preheated (to 170C-190C) fat or oil until cooked through and crisp on the outside.
While it is relatively easy to deep fry food with the correct tools (basket or spider), there are a number of things to be concerned about, first you are cooking in either fat or oil, so it’s important to remove as much of this as possible after cooking. The most common way is by shaking as much off the food as possible as soon as it is removed from the cooker and then rested on clean kitchen paper to absorb more of the oil.
It’s important to have the correct amount of fat or oil for the food you wish to cook and this should be changed regularly to avoid the build up of hydrogenated fats (a.k.a. bad stuff). It’s also vitally important to remove as much excess moisture as possible from the food before frying to prevent accidents.
In most cases a specific deep fat fryer should be used, however you could use a large saucepan. I would strongly recommend that if you are going to deep fry then use a dedicated deep fat fryer as this will have its own temperature controls and is far less likely to go on fire than any cooker top method of deep-frying. That said it’s always a good idea to have a fire-blanket and an appropriate fire extinguisher handy as well as knowing how to use them!