Combine the saffron with one tablespoon of water and set aside.
Combine the milk and yeast in the bowl of a stand mixer and let it stand for 10 minutes to activate the yeast.
Add the sugar, spelt flour, and half of the bread flour. Stir to combine.
Using the dough hook, knead until the dough until just combined.
Add the room temperature butter, the egg, the saffron with liquid, and the remaining flour.
Using the dough hook, allow the mixer to knead the dough for about 10 minutes. It should be smooth and pulling away from the sides off the bowl when it is ready.
Sprinkle the dough with a little flour, cover with a clean kitchen towel, and let rise until doubled, about 1 hour.
While the dough is rising, combine the raisins with water and set aside to plump up.
Pre-heat the oven to 200C / 400F. Line a couple of baking sheets with parchment paper, or grease well with butter.
Turn the dough out onto a lightly floured countertop, and divide into 24 pieces.
Roll each piece into a long rope (mine were about 16 inches), then coil the ends of the rope towards the center from opposite sides. Place each coiled bun onto the prepared baking sheet. Cover and let rise until almost doubled.
Brush buns with beaten egg and press a raisin into each end (two raisins per bun).
Bake on the center rack for 8-10 minutes. Buns should be puffed and golden, brown on the bottom, and sound slightly hollow when tapped.