Preheat oven to 350°F

Begin by making the muffin batter. In a large bowl, cream the softened butter and sugar together with an electric mixer until smooth, about 3-4 minutes. Add the eggs and egg yolk and mix thoroughly. Add the remaining wet ingredients (maple syrup, coffee, brandy, and sour cream) and combine thoroughly.

In another medium bowl, combine the flour, baking powder, salt, cinnamon, allspice, and nutmeg thoroughly.

Using an electric mixer on low, slowly add the dry ingredients to the wet ingredients to fully incorporate. Once completely combined, fold in the pecans.

To make the streusel, in a small bowl combine all ingredients and thoroughly mix. It should be somewhat moist, but lumpy.

In the muffin tin, fill each slot ¾ to the top with the batter. You may have a little extra batter, but do not over-fill. Generously sprinkle the streusel over each muffin.

Place the muffin tin into the preheated oven for 18-20 minutes or until a toothpick inserted into the middle of a muffin comes out clean. Remove from the oven, let cool in the tin for a few minutes and gently lift each muffin out onto a wire rack. Once cooled, drizzle with the glaze.

Mix all ingredients together in a bowl until the consistency is smooth. Drizzle over muffins.