Preheat oven to 350 degrees F. Mix together the flour, sugar, baking soda, cinnamon, and salt. Stir in the carrots, raisins, coconut, apples, and nuts (if using). In a separate bowl, beat the eggs with the oil and vanilla. Add to the flour mixture and combine well. Spoon the batter into greased or paper-lined muffin tins and bake 35 minutes.