Sprinkle yeast over water in a small bowl. Once foamy, stir in sugar and egg, then add flour and salt and beat until combined. Turn out and knead until you have a smooth, slightly sticky, elastic dough. Lightly oil the bowl (clean it first, if necessarand place the dough in it; cover and allow to rise until doubled in size, ~1 hour.
making the dough:
Line a baking sheet (or the bottom of a baking sheewith a piece of parchment paper and lightly grease it. Combine the egg yolks, orange blossom water, and water in a small bowl.
Tear the starter into pieces and place in a large bowl. Add butter and sugar and beat to combine. Beat in yolk mixture half at a time, alternating with the flour. Knead until smooth, but still slightly sticky, 10 minutes or so.
Place back in a large, oiled bowl and cover. Let rise until doubled in size, ~1 hour. Dough should be puffy and pillowy at this point.
Turn risen dough out onto a lightly floured work surface. Tuck a plastic baby (or large, dried beainside the dough from the bottom, and then push and turn the dough to form a round, pillow-shaped mass. Use your finger or fist to break a hole in the center of the dough. Very carefully lift and rotate the dough to enlarge the circle, taking care not to let the baby poke out of the dough too much (a tiny bit will be okay, because the dough will rise and enclose it).
Set the ring of dough onto the prepared baking sheet.
decorating the dough:
Decorate the dough with dried and/or candied fruit and nuts. Brush the dough with a little bit of your egg wash if you're worried about anything not sticking. If you are making the decorating paste, leave space to add it once the dough has risen.
Loosely covered with plastic wrap that has been sprayed with nonstick spray. Allow to rise until it has risen to about half its size again, 60 to 90 minutes.
Preheat oven to 350° F during the last 30 minutes of rise time.
Notes
This bread stores well, and tastes just as good if not better the second day. To store, once bread has cooled completely, slide it into a paper or plastic bag and seal.