Using a blender to mix cake batter can save the day if you don't have a hand mixer available. But you can't simply throw all the ingredients into the blender and let it rip. You risk over-mixing the batter and activating too much gluten. Gluten makes pizza crust and breads chewy, but this is not a desirable quality in cake. By blending the ingredients in a certain order, you can make a cake with the texture of one mixed with a hand mixer.
Wet Ingredients First
Start with eggs, oil, milk and other wet ingredients called for in the cake recipe. With a box mix, this could mean just water and eggs, but if you're making a homemade cake, you may need to add eggs, oil, vanilla extract, milk, water, peanut butter and other ingredients. But hold off on butter or shortening. These fats don't mix with liquid well and could cause a terminal clump at this stage. Instead, heat butter or shortening in the microwave long enough to soften it and set it aside. Pulse the blender on low until the wet ingredients thoroughly combine.
Dry Ingredients Second
Any dry ingredients other than flour go into the blender after the wet ingredients. These include cocoa powder, oatmeal, baking soda, baking powder, salt, shredded coconut and chopped nuts, among other possible ingredients. Pulse the blender just enough to distribute the dry ingredients through the wet batter. Do not add the softened butter yet, though. If the recipe calls for chocolate chips, add them after you blend in the rest of the dry ingredients. Pulse the blender on low once or twice to mix them in, but not so much that it begins chopping the chocolate chips to bits.
Flour and Butter Last
Now you're ready to add the flour. If you softened butter or shortening earlier, add it to the blender with the flour. Keep the blender on low and pulse it at 1-second intervals, just until the batter looks smooth. Let it rest for up to 10 minutes — until any bubbles dissipate — before pouring it into the prepared pan.
Baking the Cake
Pour the batter into a greased cake pan and bake it in a preheated oven for the time dictated by the recipe. Allow it to cool and then slice and serve it. Any chewiness means you overworked the flour. Next time you attempt the recipe in a blender, stop pulsing the flour a few seconds sooner than you did on the first attempt.