Preheat oven to 375 degrees and line muffin tin with paper liners, set aside.

In a large bowl, whisk flour, brown sugar, baking powder, baking soda, cinnamon and salt. Make a well in the center and set aside.

In a smaller bowl, or large measuring cup, whisk milk, butter, eggs and vanilla until smooth. Pour wet mixture into the dry bowl and mix (with a hand blender or by hand) until you have a thick but smooth batter.

For the crumb topping, stir together the flour, sugars, and cinnamon in a medium bowl. Add the melted butter and stir with a fork until the mixture is crumbly and resembles wet sand.

For the cinnamon swirl, combine the sugar and cinnamon in a small bowl.

Begin to assemble the batter inside the lined muffin tin by scooping 2 tablespoons of batter into each muffin cavity. Place a teaspoon of cinnamon sugar mixture on top, give it a quick swirl, and top with more muffin batter, filling the tin 3/4 to the top.

Sprinkle about a heaping tablespoon of crumb topping on top of each muffin top, covering the tops.

Bake muffins for 15-17 minutes until the crumbly tops are golden and when a toothpick inserted in the middle comes out clean. Remove from oven and allow muffins to cool down to room temperature in the pan prior to transferring them to a wire rack to glaze.

Once cooled, drizzle a little glaze over cooled muffins.