Apple Rosemary Upside Down Cake

INGREDIENTS

For the Cake:

2 cups

all-purpose flour

1 3/4 tsp

baking powder

1/2 tsp

fine-grain sea salt

4 oz

unsalted butter, room temperature

1/2 cup

white granulated sugar

large eggs

1 tsp

pure vanilla extract

3/4 cup

whole milk

For the Apple Topping:

6 tbsp

unsalted butter

3/4 cup

brown sugar

rosemary sprig, leaves detached

large honey crisp apple, cored and thinly sliced (equaled to about 1 cup of sliced apples)

flaked sea salt, plus more topping