Flour + water = hardtack

Flour + water + yeast = bread

Flour + water + yeast + butter = toast

Flour + water + yeast + butter + sugar = muffin

Flour + water + yeast + butter + sugar + eggs = cake

Flour + water + yeast + butter + sugar + eggs + chocolate = brownie

Flour + water + yeast + butter + sugar + eggs + chocolate + cream = cupcake