Preheat the oven to 350°F and line an 8×8-inch square cake pan with parchment paper so that the parchment stick up over the edge of the pan by a couple of inches for easy removal after baking. In a mixing bowl, whisk together the flour, sugar, baking soda, and salt.
If you have frosted this cake, it will need to be stored in the refrigerator in an airtight container. The leftovers can then be enjoyed for up to 5 days.