Browning

Two chemical processes do most of the work. The Maillard reaction between proteins and sugars creates the golden crust on bread, cookies and cakes and becomes noticeable at about 280°F (140°C) and above. Caramelization is the breakdown of sugar itself; table sugar starts to caramelize at around 320°F (160°C).

Milk, eggs, sugar and an alkaline ingredient like baking soda all speed browning. An egg wash, a higher oven temperature or a dark pan gives a deeper color, while a lighter pan or foil tent slows it down.