Pineapple Upside-Down Cake

1/2 cup salted butter

3/4 cup light brown sugar (packed)

1 can pineapple slices (20oz size)

13 maraschino cherries

½ tsp. cinnamon

1 cup flour

3/4 cup granulated sugar

2 tsp. baking powder

1/8 tsp. salt

1 large egg

1/2 cup buttermilk

1/3 cup sour cream

3 Tbsp. vegetable oil

1 Tbsp. good quality vanilla extract