Use an electric mixer on medium speed to beat the butter and brown sugar until the mixture is pale and fluffy. Beat in the eggs one at a time, followed by the vanilla.
Pour the batter into the prepared pan and bake for 55 to 60 minutes, or until the cake springs back when you gently poke it and a toothpick inserted into the center comes out clean.
Let the cake cool in the pan for an hour; carefully invert it onto a wire rack, then again onto a serving plate. Dust with confectioners’ sugar before slicing and serving.