First of all, work the butter into the strong bread flour with your fingers and then stir in the sugar and seedless raisins.
Add a pinch of salt, if using unsalted butter. Add the yeast, milk and the saffron liquid.
Carefully mix into a dough and turn on to an oiled kitchen work surface.
Knead for about 10 minutes, until smooth and then place in a lightly oiled plastic bowl. Cover with tea -towel or a plastic bag and let the dough rise for an hour or until it doubles in size.
Gently deflate the dough, divide into about 12 pieces and shape into buns by rolling them one by one under your hand.
Put the buns in your baking tray, cover with a plastic bag or something similar and let them rise for a further 30 minutes.
Brush them lightly with milk before placing in the oven.
Bake for 20 to 25 minutes in an oven pre-heated to 180°C/350°F/gas mark 4. Check that they are done with a wooden skewer or tap on the bottom of the buns. They should sound hollow, and their colour should be lightly brown/golden.