Preheat oven to 350 degrees. Spray a Jumbo muffin pan with non-stick spray.
In a medium bowl, using a whisk or a softer, combine the flour, baking powder, cinnamon, salt, and cornstarch. Set aside.
In a large bowl, add the eggs, both sugars, and vanilla. Beat until smooth.
Add in the pineapple juice and mix unti combined.
Gradually add in the dry ingredients and mix until just combined. Overmixing will result in a dense muffin.
To make the topping: Using a small saucepan, melt the butter over medium heat. Add in the brown sugar and vanilla. Whisk for one minute. Remove from heat.
Spoon about 2 tablespoons of the topping into the bottom of each jumbo muffin cup. Place a pineapple ring on top in each muffin cup. Then place a maraschino cherry in the middle of each pineapple ring.
Divide the batter equally among the muffin cups, about 3/4 of the way full.
Bake for 20-23 minutes, or until golden brown and a toothpick inserted in the center of the muffin comes out clean.
Let cool in pan about 5 minutes before removing from pan. I find it's easier to run a knife around each muffing to loosen any part that may be clinging to the sides of the pan. To make clean up easy, place a sheet of parchment or wax paper under your cooling rack prior to removing the muffins from the pan.
Place a wire cooling rack over the muffin pan and flip over to release the muffins. Gently lift each stem so that it "stands" up.
Serve warm or at room temperature.