The main difference between a cupcake and a muffin is the mixing method, not just the frosting.

The culinary distinction between these two baked goods is rooted in fat distribution and aeration. In the creaming method used for cupcakes, solid butter is beaten with sugar to create a network of tiny air bubbles. This process, often cited by the Culinary Institute of America, results in a fine-crumb structure and a soft, velvety mouthfeel characteristic of traditional cakes.Muffins rely on the 'muffin method,' which typically uses liquid fats like oil or melted butter. The goal is to combine ingredients as quickly as possible to minimize gluten development. According to food science principles, over-mixing a muffin batter leads to 'tunneling,' where large air pockets form and the texture becomes tough rather than tender and bread-like.The ratio of ingredients also differs significantly between the two. Cupcakes generally contain higher concentrations of sugar and fat, aligning with the 'High-Ratio Cake' formula established in the early 20th century. In contrast, muffins have a higher proportion of flour and liquid, placing them firmly in the category of quick breads alongside banana bread and cornbread.Even the leavening agents can vary. While both use chemical leaveners like baking powder or soda, cupcakes rely heavily on the mechanical aeration from creaming. Muffins depend almost entirely on the chemical reaction between the leavener and acidic ingredients to rise quickly in a hot oven, creating their signature domed tops.