To layer as a gift jar: Assemble the jar of cake mix by layering in the 2¼ cups all-purpose flour, then 1½ cups sugar, 3½ tsp baking powder, ½ tsp baking soda, and ½ tsp salt (the order of ingredients in the recipe card). Add a tag to label your gift and seal securely.To combine for home use: Whisk all of the ingredients together and seal in an airtight container.
To make yellow cake: Pour the entire contents of the jar into a large mixing bowl or the bowl of your stand mixer. Make a well and add these wet ingredients: 1¼ cups milk, ½ cup (1 stick) melted, cooled butter + 2 tablespoons vegetable oil, 1 tablespoon vanilla extract, and 3 large eggs (at room temperature).Mix until combined, about 1-2 minutes, then transfer into greased and floured baking pan(s).
Bake at 350°F (175°C/Gas Mark 4) for 15-18 minutes for cupcakes, 20-25 minutes for 8-inch round cake pans (2), or 32-36 minutes for a 9x13 baking pan.
