Dissolve the yeast cube in some of the lukewarm water, then stir in 600 g flour and the sugar. Cover and let rise in a warm place for 30 minutes.
Wash fresh herbs if using them, shake dry, pluck the leaves, and finely chop them. Peel the garlic and chop into thin slices.
Stir the chopped herbs, garlic, soft butter, semolina, and salt into the pre-dough. Knead in the remaining 600 g flour until the dough comes together. Cover and let rise for 30 minutes.
Divide the dough into three equal portions. Shape each into a 40 cm long roll. Braid the three rolls together. Place on a baking sheet lined with baking paper and let rise for 1 hour.
Preheat the oven to 200 °C (392 °F). Bake the braid for 45 minutes.