What makes cottage fries irresistible? It's the caramelization. Whenever you bake or sauté carrots, onions or potatoes in oil or butter, you're caramelizing - or oxidizing - the vegetables' own sugars, giving them a sweet nutty flavor and brown color. Thin potato pancakes, cooked in olive oil, covered, for 5-8 minutes on each side over medium heat, are the crunchy, delicious outcome of caramelization.
But caramelization isn't the only type of browning. When you bake bread or sear meat, caramelization is complemented or sometimes replaced by the Maillard reaction between the sugars and amino acids in the food. Food Guy Greg Patent gives the lowdown on the chemical differences between these types of non-enzymatic browning.
To caramelize, make sure you keep the food in undisturbed contact with the skillet, and the fat in it, in order to oxidize the sugars. But don't get too casual. At high heat, the process can transform a carrot into a cigarillo while your back is turned.