Preheat the oven to 300 degrees F.
Line an 8.5x4.5 loaf pan with parchment paper.
Whisk together the flour, ginger, and cinnamon in a small bowl.
Melt the butter in a pan with the molasses and brown sugar.
Once melted, add the liquid to the flour and stir well with a spatula.
Add the egg and stir.
Combine the warm milk with the baking soda and stir to combine.
Add the milk to the batter and mix until smooth.
Pour the mixture into the pan.
Bake in the oven for about 75-80 minutes until the top is springy to the touch.
Let cool for at least 2 hours before slicing.