Bring stock to a simmer in a medium saucepan over medium heat. Reduce heat to very low and simmer gently
Heat oil in a heavy-based saucepan over medium heat. Add onion and garlic and cook, stirring for 5 minutes or until soft.
Add rice and stir for 2 minutes or until grains appear slightly glassy. Add wine and cook, stirring until completely absorbed. Add ½ cup of chicken stock to the rice and stir continuously until stock is completely absorbed. Continue adding stock, one ladleful at a time, stirring continuously, allowing the liquid to be absorbed before adding more. Continue until all stock is added. Cook for 15 minutes or until the rice is tender yet firm to the bite and risotto is creamy.
Remove from heat and stir in the pancetta and parmesan. Set aside to cool completely
Line an oven tray with baking paper. Stir basil leaves through the risotto mixture. Roll 1 tablespoonful of risotto mixture into a ball. Make a large dent in the centre and place a Bambini bocconcini ball in the centre. Use wet hands to enclose cheese with risotto mixture and place on the tray. Repeat with remaining risotto and bocconcini.
Place the flour, egg and breadcrumbs in separate bowls. Dip a risotto ball in the flour to lightly coat, then dip in egg, then coat in breadcrumbs, shaking off excess. Place on a lined tray. Continue with remaining risotto balls. Repeat, dipping each ball in egg then breadcrumbs so they are coated twice. Cover with plastic wrap and place in the fridge for 30 minutes to set.
dd enough oil to a medium saucepan to reach a depth of 6cm and place over high heat to 180°C (to test when oil is ready, a cube of bread turns golden brown in 15 seconds). Place 1/3 of the arancini in the hot oil and cook for 3-4 minutes or until golden brown all over and heated through. Use a slotted spoon to transfer to a plate lined with paper towel. Repeat in 2 more batches with remaining balls, reheating oil between batches. Place on a serving platter and serve immediately.