Torta di rose with ricotta filling (ricotta "roses")

Dough

• 230 g milk
• 60 g salted butter, cut into pieces
• 20 g white sugar
• 2 tsp dried instant yeast
• 1 egg
• 500 g plain flour
• 1 tsp salt

Ricotta filling

• 500 g ricotta (see Tips)
• 50 g white sugar
• 80 g dark chocolate chips
• 40 g candied citrus peel (see Tips)
• 1 tsp natural vanilla extract
• 1 egg yolk, lightly beaten