Preheat the oven to 350 degrees. Line a standard 12-cup muffin-tin with paper liners.
In a medium bowl, combine chopped almonds, brown sugar, and cinnamon. Mix well and set aside.
In a large bowl, combine flour, sugar, and salt. Cut 8 tablespoons of butter into ½ inch pieces and sprinkle evenly over flour mixture. Using a pastry blender, cut the butter into the flour mixture until butter is oat-sized. Remove 1 cup of the flour-butter mixture and stir into reserved brown sugar mixture until combined to make streusel; set aside. Add baking powder and baking soda to remaining flour mixture and stir to combine.
In a liquid measuring cup, whisk together sour cream, egg, and vanilla. Add liquids to flour mixture and stir until just combined. Add 3/4 cup of streusel mixture to flour mixture and stir until streusel is just distributed throughout batter. Melt the remaining butter and stir into remaining streusel mixture, until streusel resembles a crumble. Gently fold blueberries into batter.
Divide batter among 12 muffin cups and sprinkle generously with streusel topping, crumbling with your hands to make some big chunks. Bake 22 to 24 minutes, or until a toothpick inserted in the center of muffin comes out clean.
Allow to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
To make the glaze, whisk the confectioners' sugar, milk and vanilla extract together. Drizzle over muffins. Store in a sealed container for up to 2 days.
*Nutritional information is an estimate. Please consult a doctor or nutritionist for the most accurate nutritional info.