In a processor or by hand, add the yeast, 1 tsp of maple syrup, and lukewarm water. Let stand for five minutes.
When the mixture is foamy, add the oat milk, coconut oil, salt, cinnamon, nutmeg, maple syrup or brown rice syrup, orange zest, lemon zest, baking powder and 1 cup of flour. Mix together with a wooden spoon.
Add 2.5 cups of flour and knead together with your hands.
If the dough sticks together, add a little more flour and keep kneading until it is not.
Add the raisins and cranberries and knead until mixed through.
Lightly oil the inside of a medium glass bowl. Place the mixture in to the bowl and cover with a towel. Let it sit for about an hour.
After an hour, knead for a further minute.
Line an 11 x 13 inch pan with greaseproof paper.
Separate dough into 12 equal pieces and roll each one in to a ball and place on the pan.
Cover with a towel for a further 30 minutes. Preheat oven to 180C.
Make the flour and water paste for the crosses. Just add enough water to the 5 tablespoons of flour to make a thick paste for piping. Remove the towel from the buns, fill a piping bag or piping syringe with the paste and pipe a cross shape on each bun.
Brush a little oat milk over them just before placing in the oven and bake for 20 minutes.
Remove from the oven and cool on a rack. Once cooled separate the buns and serve.