Combine 3 cups of flour, brown sugar, yeast and salt in the mixing bowl of an electric mixer using the dough hook.
Add the water, butter and egg to the flour mix and beat on medium-high for 2 minutes. Mix in Gingerbread Butter. Slowly add additional cup of flour until the dough forms into a ball. Beat for 2 minutes.
Turn dough onto a (lightly) flour covered surface. Knead dough by hand, adding more flour as needed, until dough is smooth and elastic, for about 5 minutes. Cover with towel and let rest for 15 minutes.
While the dough is resting, combine the butter and gingerbread butter for the filling. In a separate bowl combine the brown sugar, cinnamon and nutmeg.
Roll dough into a large rectangle so the dough is about ½ inch thick. Spread the butter mixture over the dough leaving the outer ½ inches clean on each side. Sprinkle the sugar mixture on top and add any additional nuts or raisins if desired.
Beginning at the long end, roll the dough tightly and pinch the seams closed. Using a sharp knife, cut into 12 rolls and place on a parchment lined baking sheet. Cover with a towel and let rise for 1 hour until double in size. Meanwhile, preheat oven to 350°F.
Once the rolls have doubled in size, bake at 350°F for 20-25 minutes until golden brown. Remove from pan and place on cooling rack.
Combine all glaze ingredients in a mixing bowl and beat until smooth. Top Gingerbread Cinnamon Buns with glaze while slightly warm and serve warm.