Spiced Pear Upside Down Cake

1/4 cup butter 

3/4 cup packed brown sugar

2 pears, peeled

1 teaspoon pumpkin pie spice

1 package (15.25 ounces) yellow cake mix

1 cup water

1/3 cup softened butter

3 eggs

Heat oven to 350 degrees. Place butter in a 9″ round cake pan and heat in oven until butter is melted. Sprinkle brown sugar evenly over butter. Cut peeled pears in half lengthwise and remove cores. Cut pears again lengthwise in 1/4″ thick slices and place in a large bowl. Sprinkle pears with pumpkin pie spice and gently toss to coat. Arrange pear slices over the butter mixture in pan, slightly overlapping. Prepare cake batter as directed on package using water, butter, and eggs. Carefully spoon cake batter over the pears. Bake cake at 350 degrees for about 45 minutes until a toothpick inserted into the center of the cake comes out clean. Cool the cake for 5 minutes on a wire rack, then carefully invert cake onto a serving plate.