In a medium bowl, mix together flour, baking powder, baking soda, and salt. Set aside. In a large microwave-safe bowl, melt butter in the microwave. Whisk in sugar – mixture will be gritty. Chill in the refrigerator for 1 minute. Stir in egg, yogurt, milk, and vanilla extract until combined. Slowly mix in dry ingredients until no lumps remain. Batter will be thick. Slowly stir in sprinkles, but do not overmix because the sprinkles will bleed their color.