Preheat the oven to 350° F. Put 22 liners in muffin pans. In an electric mixer with the paddle blade, cream the butter. Add the sugar and cream for about 3 minutes. Add the eggs one at a time. then add the vanilla, sour cream, milk and lemon zest. Sift together the flour, baking powder, baking soda and salt. Add to the mixer on low speed. Fold in the blueberries. Scoop into muffin tins. Top with the strudel mix and bake for 25 minutes or until a toothpick comes out clean. Bon Appetit.