Preheat oven to 350°. In a large mixing bowl, combine 1 stick of butter, 2 eggs, and milk with the Vanilla Cake Mix; set aside. In a small saucepan over medium heat, combine the brown sugar and remaining 1/4 stick of butter; mix until all the brown sugar has dissolved (about 5 minutes). Carefully pour the syrup into the bottom of a cake pan, lay the pineapple pieces over the syrup, and then fill with the cake mix. Place inside the oven for 40 to 50 minutes, or until you can pierce the center with a toothpick, and have it come out clean (also you can give it a quick shake; if it jiggles like gelatin, give it more time). Let cool, then stand on your head and enjoy! (Joking.) Carefully put a plate over the cake pan and flip it over so the pineapples are on top- now it's time for serious enjoyment.