Preheat oven to 350°F. 

Combine cake mix, water, oil and eggs in a large bowl. Mix with a handheld mixer or with a whisk until smooth. 

Remove two cups of batter and pour into a separate bowl. Mix the blue food coloring into this bowl. 

Set remaining batter aside. 

Pour the blue batter into a half sheet tray (or a 9x13 baking pan) and bake for 20 minutes, until a toothpick inserted in center comes out clean. 

Cool completely.

Using a dreidel cookie cutter (about 2 inches tall), punch out dreidel shapes from the cooled blue cake. 

Grease an 8-inch loaf pan and pour in 1 cup of the reserved batter. 

Line the blue dreidel cake pieces standing up, in an even row, and press into batter. 

Pour remaining batter into loaf pan. 

Bake the cake for 35 minutes. 

Cool and serve as is, with frosting or a dusting of powdered sugar.