Preheat your oven to 400°F (200°C). Line a muffin tin with paper liners or lightly grease the cups.

In a large mixing bowl, whisk together 2 cups of all-purpose flour, ¾ cup granulated sugar, 2 teaspoons of baking powder, and ½ teaspoon of salt.

Melt ½ cup of unsalted butter and whisk in 1 egg, 1 cup of whole milk, and 1 teaspoon of vanilla extract until smooth.

Pour the wet mixture into the bowl of dry ingredients and stir until just combined.

Gently fold in 2 cups of fresh blueberries until well-coated with batter.

In a small bowl, mix together ½ cup of all-purpose flour, ½ cup of brown sugar, and 1 teaspoon of cinnamon. Add ¼ cup of cold unsalted butter and mix until crumbly.

Fill each muffin cup about two-thirds full with batter and sprinkle the crumb topping over them.

Bake in the preheated oven for 5 minutes, then reduce the temperature to 375°F (190°C) and bake for 15-18 minutes.

Remove from the oven and let cool in the pan for about 5 minutes before transferring to a wire rack.