These are the best blueberry crumb muffins! They're tender, bursting with fresh blueberries, and feature an easy crumb topping that takes this baked good favorite over the top.
I rarely have buttermilk on hand, so I make a quick and dirty version with regular milk and vinegar. For this recipe, add 2 tsp of white vinegar to a measuring cup and pour in milk (I used 2%) up to the 2/3 cup marking. Give it a stir and let it sit for at least five minutes before adding to the recipe.