• Preheat the oven to 400℉
• In a bowl, whisk together the eggs, buttermilk, butter. In a separate bowl, mix the flour, sugar, baking powder and salt together. Now, combine the dry and wet ingredients until everything is combined.
• Fold in the blueberries into the batter. Then, add the muffin liners into the tray and fill 3/4 of batter to the top.
• For the topping instructions, see below. Sprinkle the crumbles across the tops of the muffins and press down slightly on each.
• Place the muffin pan into the oven for 15 minutes. The tops should be slightly golden and you can insert a toothpick in the center of a muffin and it come out clean.
• Allow the muffins to cool for about 20 minutes before serving, enjoy.

Topping

• In a bowl, combine all the ingredients minus the butter. A pastry cutter or a potato mashed works great. If not, you can squeeze or hand mix the ingredients together but this will take some time.
• Cut or press the butter into the dry ingredients until crumbles are formed. Follow the steps above as normal after that.