Pineapple Upside-Down Cupcakes

Place a rack in the center of oven and preheat to 350 ºF. Lightly mist 24 cupcake cups with cooking spray and dust with flour. For the topping, measure 1 tsp. of melted butter into each cupcake cup. Sprinkle 1 heaping teaspoon brown sugar on top of the butter. Spread about 1 Tbsp. pineapple on top of the sugar and place a maraschino cherry half in the center of the pineapple, pushing it down so the cherry touches the pan. Set pans aside. For the cupcakes, blend cake mix, sour cream, pineapple juice, oil, eggs and vanilla in a large bowl with an electric mixer on low speed for 30 seconds; scrape down the sides of the bowl with a rubber spatula. Increase the mixer speed to medium and beat for 2 minutes more, or until batter is thick and smooth, scraping bowl again if needed. Spoon 1 ⁄3 cup batter onto the topping in each cupcake cup. Bake until cakes are golden and spring back when lightly pressed with your finger, 18 to 20 minutes. Immediately run a knife around the edges of the cupcakes to loosen. Invert onto a platter and cool for at least 15 minutes before serving.