Single-Serving Size Oatmeal Chocolate Chip Cookies

and 1/2 tablespoons brown sugar (lightly packed)

and 1/2 tablespoons white sugar

unsatled butter (at room temperature)

vanilla

large egg yolk (reserve whites for another recipe or discard)

old-fashioned oats

scant 1/8 teaspoon salt

cinnamon (optional)

flour

baking powder

baking soda

and 1/2 tablespoons milk chocolate chips