Apple-Molasses Upside-Down Cake

INGREDIENTS

• 5 unsalted butter
• 1 3/4 all-purpose flour
• 1 1/2 kosher salt
• 1 ground cinnamon
• 3/4 baking soda
• 1/2 baking powder
• 3/4 mild-flavored (light) molasses
• 1 large egg
• 2 grated peeled ginger
• 1/2 sugar, divided
• 1/3 sour cream
• 1/4 whole milk
• 3-4 Honeycrisp or Pink Lady apples, (about 2 pounds), peeled