Lemon Crumb Muffins - Sift all dry ingredients together.
Grate the rind of five lemons, set the lemons aside.
Whisk eggs and add sour cream, butter, lemon juice and whisk until smooth.
Fold in lemon rind.
Fold all dry ingredients into the egg mixture and blend well.
Struesel - Sift sugar and flour together. Add softened butter and work into dry ingredients until smooth.
Lemon Glaze - Sift together until all of the sugar is dissolved.
Preheat oven to 350. Spray muffin tins and fill with lemon muffin batter. Top with 1 T struesel. Bake at 350 for 18-20 minutes. (325 for convection oven). Poke muffins several times with a toothpick, drizzle top with 1/2 tsp. lemon glaze. Remove from muffin tin, and store in airtight container. Yield: 24-30 muffins. Note: Batter can be kept up to one week in refrigerator.