The main difference between shallow frying and deep frying is how much oil you use; shallow frying cooks food partially submerged in oil, while deep frying covers it completely.
Think of shallow frying, also known as pan-frying, as giving your food a nice warm bath in oil, but only up to its waist! You're cooking it in a pan with just enough hot oil or fat to cover about half its thickness. This method relies on the direct heat from the pan and the hot oil to cook the food and create that lovely crispy outside. It's like cooking on a hot plate with a bit of a sizzle. Deep frying, on the other hand, is a full immersion experience. You completely dunk your food in a much larger amount of hot oil. This way, every side gets cooked and browned at the same time, giving you a really uniform and usually extra-crispy result. The heat in deep frying mostly comes from the hot oil all around the food.
Always make sure your oil is hot enough for shallow frying before you add food. If it's not, your food will just soak up the oil and end up greasy, not crispy!