In a mixing bowl, cream butter and sugar. Add eggs, one at a time, beating well after each addition. Combine flour, baking powder and baking soda; add alternately with sour cream to creamed mixture, beating well after each addition. Fold in sausage and blueberries.
Pour into greased 13 x 9 x 2-inch baking pan. Sprinkle with pecans. Bake at 350 ºF for 35-40 minutes or until cake test done.
For sauce, combine sugar and cornstarch in saucepan. Add water and blueberries. Cook and stir until thick and bubbly. Spoon over individual serving.