The relationship between energy and mass came out of another of Einstein's ideas, special relativity, which was a radical new way to relate the motions of objects in the universe. At one level, the equation is devastatingly simple.
Time and Tools. The most obvious difference between a cake and a cupcake is size, which depends on the container in which the dessert is prepared. Cakes are baked in large pans, usually round or square, and take half an hour or more to bake fully. Cupcakes, on the other hand, are baked in tins with several cups. Each cup is much smaller than a large cake pan, so a batch of cupcakes usually takes only about 15 minutes to bake.
Preheat oven to 350 degrees F (175 degrees C). Grease a 12 cup muffin pan or line with paper baking cups. In a large bowl, mix butter and sugar with an electric mixer until light and fluffy, about 5 minutes. Stir in the eggs, one at a time, blending well after each one. Stir in the vanilla and flour just until mixed. Spoon the batter into the prepared cups, dividing evenly. Bake in the preheated oven until the tops spring back when lightly pressed, 18 to 20 minutes. Cool in the pan set over a wire rack. When cool, arrange the cupcakes on a serving platter.