Preheat the oven to 350 degrees and line a 12-cavity muffin tin pan with liners.
Making the Coffee Cake Muffins:
(1) In a small mixing bowl combine the brown sugar, cinnamon and nuts. (2) In a large mixing bowl combine the dry ingredients: flour, sugar, baking powder, baking soda and salt. (3) In another medium/large mixing bowl combine the wet ingredients: egg, milk and oil. Whisk to fully combine.
Stir the wet ingredient into the dry ingredients, whisking together just until combined (do not over mix).
Spoon/scoop 1 tablespoon of batter into each muffin liner. Sprinkle 1 teaspoon of the sugar-nut mixture on top followed by 2 more tablespoons of batter. TIP: add the batter to each muffin cavity, followed by the sugar-nut mixture and the remaining batter to ensure equal distribution. Finish with a teaspoon of sugar-nut mixture on top.
Bake for 22-25 minutes until a toothpick inserted in the center of muffins comes out clean. Allow to cool in the muffin pan while you make the glaze.
To glaze the Coffee Cake Muffins:
Line a rimmed baking sheet with foil and place a cooling rack on top.
In a small bowl mix together all the glaze ingredients.
Place the muffins on the cooling rack allowing space between them. Take a dining spoon of glaze and holding the spoon over a muffin, shake it back and forth while moving it around allowing the glaze to drizzle onto the top of the muffin.
Repeat for all the muffins and allow the glaze to harden for 5-10 minutes before eating.