Combine cream cheese, sugar and margarine, mixing until well blended.
Add eggs, one at a time, mixing well after each addition.
Blend in vanilla.
Add combined dry ingredients alternately with milk, mixing well after each addition.
Pour into greased and floured 13x9-inch baking pan; dot with preserves.
Cut through batter with knife several times for marble effect.
Bake at 350°, 35 minutes.