• Preheat the oven to 400 °F (204 °C)
  
• Put the pastry blade in the food processor
  
• 1 1/2 cup Flour, 1/4 cup Sugar, 3 tablespoon baking powder, 1/2 teaspoon salt
  Put the dry ingredients into the bowl of the food processor. Whir it around to mix.
  
• 1/4 cup unsalted butter
  Add the butter.
  
• process just until the mixture looks like sand
  
• 1 Egg
  Add the egg
  
• 1 cup sour cream, 1/2 teaspoon vanilla
  Add the sour cream and vanilla
  
• Process until the mixture comes together
  
• 1 cup Blueberries
  Finally, add the blueberries
  
• Process just until the blueberries are stirred in.
  
• Remove the batter from the bowl of the processor into a measuring cup or bowl with a spout. Wash the food processor bowl.

Crumb Topping

• Put the small bowl into the large bowl of the food processor and secure it.
  
• 1/4 cup unsalted butter, 2 tablespoon brown sugar, 1/2 teaspoon cinnamon, 1/2 cup Flour
  Add the butter, flour, brown sugar, and cinnamon.
  
• Process it just until it comes together into a nice crumble.
• Grease muffin tins and pour the batter into the tins about 2/3 full.
  
• Sprinkle the crumb topping on the muffins generously.
  
• Bake in the oven for 20 to 25 minutes or until the tops have started to brown.
  
• Remove from the oven and let sit for about 10 minutes to cool.
• Serve with butter and enjoy!