In a large bowl of a stand mixer add flour, xanthan gum, psyllium husk, mixed spice and dried yeast. Stir to combine and then make a well in the centre.
In a microwave, heat milk and water in a small bowl until lukewarm (about 40 seconds on high). Add egg and oil and whisk with a fork to combine. Pour liquid into dry ingredients and stir using a paddle attachment for 2 minutes or until a sticky, dough consistency. Cover with a tea towel and rest for 1 hour in a warm spot.
Divide mixture into 12 balls. Place on a lined tray with baking paper, cover and rest for a further 30 minutes or until nearly doubled in size.
To make the crosses, mix flour and water until a thick runny paste. Spoon into a piping bag (approx 3mm tip) and pipe crosses onto buns.
Meanwhile, preheat oven to 180°C fan-forced. Bake for 30 minutes, until golden brown. Remove from oven and brush with warmed apricot jam.