Preheat your oven to 350°.
Spray the inside of 2 jumbo muffin pans with non-stick spray. Into each muffin cup, spoon 1 teaspoon of melted butter and sprinkle in 1 tablespoon of dark brown sugar. Lay a pineapple ring on top of that. It should fit perfectly. If it doesn't, just trim out a piece of each ring until it fits. You can eat that bit, that's fine. It's fruit. As you can see, I had to do exactly that in one of my pans. And yes, my pans are mismatched. I don't even remember buying these pans, so welcome to real life. We adjust.
Place a maraschino cherry in the center of each ring. Isn't that pretty? Let's make some cake.
Whisk together the flour, salt, sugar, and baking powder in a large bowl. In a small bowl, whisk together your eggs, melted butter, vanilla, pineapple juice, and sour cream. Pour the wet ingredients into the dry ingredients and mix until fully combined.
Fill each muffin cup 2/3 full. You should have just enough batter to fill each one. If you have a little batter left over, just distribute it evenly amongst all the muffin cups. Tap your pans lightly against the counter to remove any large air bubbles.
Bake at 350° for 20-25 minutes, or until a toothpick inserted in the center of a cake comes out clean. They will look delightfully fluffy and golden! See?!
Allow the cakes to cool for 5-10 minutes in the pan.
Here's the cool part that will make you feel totally chef-y. Use a potholder to hold the bottom of the muffin pan (remember, it's still warm!), and then place a sheet pan over the top of the muffin pan. Grip securely with both hands, and flip it all over in one quick motion. Give it a little shake and all the cakes should come out easily. You'll be able to hear and feel when they've all dropped down onto the sheet pan. It's okay if one or two pineapples stay in the muffin pan. Just gently remove them and place them on their cakes. They'll taste just as delightful. If it still looks a little wonky and you're not-so-sure about it, just eat those first for quality control. Share the rest with friends and family. Or not. You did all the hard work. You get to decide who is cake worthy.