Yorkshire Parkin

Preheat the oven to 350°F. Grease a 9x9-inch baking tin with butter and line it with parchment paper.
Place the butter, golden syrup, and black treacle in a heavy-based medium saucepan. Stir over medium heat until the butter is melted and the mixture is combined.
Beat the eggs with the milk until the mixture is smooth and set aside.
Whisk the flour, ginger, baking soda, mixed spice, and salt in a large bowl until well mixed. Add the dark brown sugar and stir well.
Pour in the butter mixture and stir until combined, then stir in the egg mixture. Mix only until no pockets of flour remain.
Pour the batter into the prepared pan and smooth the top. Bake at 350°F for 40-45 minutes, or until the cake is richly browned, crusty, and springy to the touch; it may sink a little in the center. A toothpick inserted into the center should come out clean.
Let the parkin cool completely on a wire rack, about 1 hour, then turn it out of the tin, peel off the parchment, and cut into squares or fingers.
Enjoy at room temperature with a cup of tea. Store the cake wrapped in parchment inside a metal tin; the cake will improve with age and tastes even better after sitting for 3-5 days. It will keep at room temperature for up to 2 weeks.