Preheat oven to 375°F. Line cookie sheet with parchment paper for baking.
In a small bowl prepare the topping by stirring flour, brown sugar, chopped walnuts, and cinnamon.
With a blender add butter and blend the mixture until it resembles coarse crumbs and set aside.
In large mixing bowl add flour, sugar, baking powder, salt and stir all together.
With a blender or fork add the butter cut into 1/2 inch cubes to the flour mixture. Mix until the mixture resembles coarse crumbs.
In another bowl, add milk, eggs, and lemon zest and stir well together.
Add egg mixture to flour mixture stir well until combined.
Flour hands lightly and gently knead the blueberries into the dough until berries are evenly distributed. The dough will be sticky.
Lightly flour hands again, and place dough on floured cutting board. Pat dough into 1-inch thickness.
Sprinkle topping mixture evenly over the top of the dough to cover. Press crumb topping lightly to the dough. Now using a 2 ½ inch cookie cutter or glass, cut out rounds of dough and place on a cookie sheet. Gather all scraps together and repeat until all the dough is used. I use the scrapes and cut out smaller ones to freeze for later. (Scones can also be made and baked without crumb topping, just brush tops lightly with milk and bake)
Place in oven and bake for 20 minutes or until dough is lightly browned. You may test with a toothpick in the center of the scone to see if it comes out clean.
Take scones out of oven and with a spatula transfer scones to a wire rack to cool for 5 minutes.
Scones are best the day they are made, or store in an airtight container in the refrigerator for 2-3 days! Enjoy.
Notes
You may freeze cut out dough to save it for later. Place scones in a container or bag suitable for freezing and label with name and date when frozen. Freeze up to 3 months.