This delicious cake is a twist on the classic pineapple upside-down cake. The sweet and tangy combination of strawberries and rhubarb is the perfect topping for a moist and fluffy vanilla cake. To make this cake, start by melting butter and brown sugar in a skillet, then add sliced rhubarb and strawberries. Pour the cake batter over the fruit and bake until golden brown. Once the cake is done, flip it over onto a serving platter to reveal the beautiful fruit topping. Serve warm with a dollop of whipped cream or vanilla ice cream.