Preheat oven to 350 degrees F. Grease and flour a 9 in round cake pan
In a medium bowl, cream together the sugar and butter. Beat in the eggs, one at a time, then stir in the vanilla. Combine flour and baking powder, add to the creamed mixture and mix well. Stir in the milk until batter is smooth. Set aside for while you complete next step.
In a small sauce pan, heat 1/2 of the juice from the can of pears and the brown sugar. While this is heating, line the bottom of the floured/greased cake pan with sliced pear in a pattern of your choice. Stir the sugar mixture on the stove, until it reaches syrup consistency. Pour over pears, then pour cake batter over this.
Bake for 30 to 40 minutes in the preheated oven, until golden brown, and the center comes clean with the insertion of a toothpick.
After cake has cooled a bit in the pan, cut off any rounded areas on top, so that it is flat on bottom. Place cake plate over the cake pan, and flip onto plate. Let cool the rest of the way, and slowly lift cake pan from plate.
Serve with some Vanilla ice cream or perhaps some pear ice cream.