Step 1

Preheat oven to 350°F.

Step 2

Place the flour, sugar, baking soda, and salt in an ungreased 8x8-inch pan. Stir with a fork to combine.

Step 3

Make three wells in the flour mixture, and pour the vanilla into one well, the vinegar into another well, and the oil into the final well.

Step 4

Pour the water over the top, and stir with a fork to combine.

Step 5

Stir in the sprinkles. Check the edges of the dish to make sure no dry ingredients have gathered there, and mix just until combined.

Step 6

Bake the cake for 30–35 minutes, or until a toothpick inserted into the center comes out clean.

Step 7

Place the softened butter, powdered sugar, vanilla, and milk into a large bowl.

Step 8

Mix with a hand mixer until light and fluffy. Spread over the cooled cake, and top with additional sprinkles.