1. Preheat the oven to 375 degrees F. Line a muffin tin with liners.
2. In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt. In a smaller bowl, combine the buttermilk, melted butter and egg. Add the wet mixture into the dry and stir until just combined. Fold in the blueberries.
3. To prepare the streusel topping, combine the almonds, brown sugar, flour, cinnamon and butter in a bowl.
4. Divide the muffin batter evenly between the liners and then spoon the streusel mixture on top. Bake for 20-25 minutes.