1. Dissolve the yeast and sugar in 275ml lukewarm water. Ensure that the water is warm, not cold or hot. Leave for 10 minutes. It should get nice and frothy, indicating that the yeast is alive and well.
2. Sift together the flour and salt, to introduce air. Rub in the butter. Add the wet to the dry ingredients and mix until combined. Knead for about 10 minutes, until the dough is smooth and elastic. It will go from rough to a little shiny. Place in a bowl, cover with cling film, and leave in a warm place for 45 minutes.
3. Remove from the bowl and knock back, pushing the air out the dough. Rest for 15 minutes, to give the gluten time to relax; this will make shaping easier. Divide the dough into eight pieces. Roll each piece into a ball. Rest for five minutes more, covered.
4. Dust a baking dish with flour and place in the balls, side by side. Dredge with flour. Leave in a warm place for 50 minutes.
5. Preheat the oven to 210°C/410°F/gas mark 6½. Dredge the blaas with flour for a final time and bake for 15–20 minutes.