Preheat your oven to 400°F (200°C). Spread the walnuts in a single layer on a baking sheet and toast them in the oven for 7-8 minutes, stirring halfway through.

In a large mixing bowl, sift together the all-purpose flour, baking powder, cinnamon, nutmeg, and salt.

In a separate bowl, beat the softened butter and brown sugar together until the mixture is light and fluffy, about 3-4 minutes.

Add in the eggs one at a time, mixing well after each addition. Pour in the maple syrup, milk, and maple extract.

Carefully fold the wet ingredients into the bowl of dry ingredients using a spatula.

Gently fold in the toasted walnuts with your spatula.

Line a muffin tin with paper liners or grease it generously with butter. Spoon the muffin batter evenly into each liner, filling them about two-thirds full.

In a small bowl, mix together flour, sugars, softened butter, finely chopped walnuts, and a sprinkle of cinnamon until crumbly.

Place the muffin tin in the preheated oven and bake at 400°F (200°C) for 5 minutes, then reduce the temperature to 375°F (190°C) and continue baking for an additional 16-17 minutes.

Once baked, remove the muffins from the oven and let them cool in the pan for about 5 minutes before transferring them to a wire rack.

Prepare the maple glaze by whisking together icing sugar, milk, maple syrup, and maple extract. Drizzle over the cooled muffins.