Easter Saffron Wreath Bread (with a Simple Glaze)

Name: Easter Saffron Wreath Bread (with a Simple Glaze)
Ingredients: 50g (3½ tbsp) butter; ½ gram (¼ tsp) ground saffron; 200ml (⅘ cup) milk; 14g (4 tsps) dried yeast (see note 1); 1 egg; 100g (½ cup) sugar; 360-480g (3-4 cups) spelt flour (see note 2); 1 tsp salt; 1 small egg (for the egg wash); 1 tablespoon milk; icing / powdered / confectioners' sugar; marzipan eggs (optional)