Slow Cooker Pineapple Upside Down Cake

for the fruit

unsalted butter, melted

agave

pineapple rings, canned in 100% juice

cherries (fresh and pitted or frozen and thawed)

for the cake

whole wheat pastry flour (measured correctly)

baking powder

baking soda

salt

unsalted butter, melted and cooled slightly

large egg, room temperature

vanilla extract

powdered Stevia

Truvia

plain nonfat Greek yogurt

nonfat milk