Prepare Crumb Topping, below and set aside. Grease and flour 9 inch pan. Preheat oven to 350 degrees. In large bowl, with mixer at low speed, beat flour, sugar, butter, milk, baking powder, cinnamon and eggs until just blended, occasionally scraping the bowl. Continue beating 1 minute. Gently fold in grated lemon peel, walnuts and half the blueberries. Spoon batter into prepared pan.
Evenly sprinkle top of batter with remaining blueberries, then with crumb topping. Bake coffeecake 60-65 minutes until toothpick inserted in center of cake comes out clean and Crumb Topping is golden brown. Serve warm or cold. Makes 12 servings.
Crumb Topping: In 1 quart saucepan over low heat, heat 4 tablespoons butter until melted. Stir in 1/2 cup flour and 2 tablespoons sugar until mixture forms a soft dough. Remove saucepan from heat.
