Blueberry-Filled Muffins

Directions

1. In a large bowl, combine the flour, sugar, baking powder, baking soda and salt. In another bowl, whisk the eggs, buttermilk and butter. Stir into dry ingredients just until moistened. Stir in lemon zest.
2. Fill greased or paper-lined muffin cups one-third full. Drop preserves by teaspoonfuls into the center of each muffin. Top with remaining batter. For topping, in a small bowl, combine brown sugar and flour; cut in butter until crumbly. Stir in walnuts. Sprinkle over tops.
3. Bake at 375° for 18-20 minutes or until a toothpick inserted in muffin comes out clean. Cool for 5 minutes before removing from pans to wire racks. Serve warm.