In a small bowl, mix together yeast, 2 tablespoons sugar and warm milk and set aside for 15 minutes.
In a large bowl, combine flour, sugar and salt. Add the egg yolks, softened butter, raisins, zest, and yeast mixture.
Knead until dough is smooth and elastic. Transfer to a greased bowl, cover with greased plastic wrap and let rise in a warm place until doubled (2 hours).
Punch down dough and knead until all the air pockets are removed.
Divide the dough into at leat three strands. Cover and let rest another 15 minutes.Braid the strands and tuck the ends under.
Place on a parchment-lined sheet pan. Cover with greased plastic and let rise until almost doubled.
Heat oven to 180°C. Bake for 30 minutes. Lightly brush bread with the eggwash and sprinkle with almonds, if using.
Bake an additional half hour. Remove from oven and let cool completely on a wire rack.