In a small jug add yeast to warm milk and stir to mix.
In a medium bowl, add sugar, flour, salt, eggs, butter and milk & yeast mixture. Using an electric mixer, beat for about 2 minutes until fully combined.
Cover bowl with tea towel and set aside in a warm place for 60 minutes to allow mixture to rise a little.
Line baking trays with baking paper and set aside.
Heavily dust a working surface and scoop golf ball sized clumps of dough from the bowl, dust with flour and roll into a ball, then place on the baking tray. You will make about 18 dough balls.
Not: This is a particularly sticky and messy step and your hands will get very sticky with dough. You will need plenty of flour during this step.. I found this step easiest by using a spatula to get a clump of dough from the bowl, then place it immediately onto the flour on the work surface. Try to coat the dough fully to allow you to work it into a ball. Keep your hands coated with flour as best you can.
Cover the baking trays with tea towels and set aside in a warm place for about 30 minutes.
In a medium saucepan over medium low heat, add vegetable oil to about 2 cm depth. Heat oil to approx 160°C (320°F).
Once temperature has been reach place about 4 dough balls into the oil and cook for about 4 minutes.
Note: the dough balls will start to expand when they cook in the oil. I like continually spoon oil onto the top of each dough ball as it is cooking. This helps to make each dough ball form a more rounded shape. Cook each dough ball about 2 minutes each side.
Remove each dough ball using a slotted spoon and place onto a plate lined with paper towel to lightly drain.
Roll each dough ball in a bowl of cinnamon sugar to fully coat each bombolini.
Add water to a saucepan over medium high heat.
Add thickened cream and dark chocolate to a medium bowl and place over the saucepan.
Allow the heat to melt the chocolate and cream mixture. Stir regularly until the chocolate is fully melted and mixture is smooth. Remove from heat.
Serve bombolini warm with warm chocolate sauce for dipping.