In a small bowl, combine warm milk, warm water, 1 tablespoon of light brown sugar, and active dried yeast. Let it sit for about 2 minutes until frothy.

In a large mixing bowl, stir in 2 cups of bread flour into the yeast mixture and mix until a rough dough forms. Let it rise for 30 minutes.

Melt the unsalted butter, then whisk together with remaining sugar, egg, salt, mixed spice, cinnamon, vanilla extract, and sultanas.

Combine the yeast dough with the butter mixture, gradually adding remaining flour until a cohesive dough forms.

Transfer the dough to a floured surface and knead for about 10 minutes until smooth and elastic.

Divide the kneaded dough into equal portions, shape into balls, arrange on a lined baking tray, cover, and let rise for 30 to 60 minutes.

For the crosses, mix flour and enough water to create a paste. Pipe the mixture over the buns.

Bake buns in a preheated oven at 220°C (425°F) for 15 to 20 minutes until golden brown.

Prepare the glaze by mixing maple syrup with water. Brush over buns after baking.