In a large bowl, stir together starter, oil, water, eggs ad brown sugar. Sift in flour, salt, baking soda and lime zest; stir just until combined-do not over mix. Gently fold in blackberries. Spoon batter into greased muffin tins, filling cups 2/3 full. Bake at 375 for 30 to 35 minutes. Remove muffins from muffin pan and cool on wire rack.Optional: Make Lime Glaze. In medium bowl, whisk together powdered sugar, lime juice and milk or cream. Drizzle over cooled muffins. Makes 6 jumbo muffins