To make marinara sauce, add all ingredients in a saucepan over medium heat and stir well. Bring to a boil and reduce heat to simmer. Simmer sauce for 20 mins.
To make risotto, heat vegetable stock and keep warm. In a large pot, heat oil over medium heat.
Add onions and saute for 1-2 minutes until soft and transluscent. Add rice and cook for 2 minutes.
Add wine to deglaze pan. Stir until wine has almost evaporated.
Add spinach and cook for 1 minute.
Add in 1 cup of vegetable stock and stir constantly until rice has absorbed most of the liquid. Repeat with remaining stock, one cup at a time.
Add in butter and stir until melted. Mix in parmigiana and season with salt and and fresh ground pepper. Let risotto cool completely.
Beat egg yolks and mix into risotto. Then mix in the halloumi and mozzarella cheese.
To make Arancini, fill a deep frying pan with oil 1/3 of the way up and heat over medium heat until temperature reaches 350F.
Mix seasoned Italian bread crumbs and panko together and place on a large plate.
Whisk egg whites in a medium bowl and season with salt and pepper.
Scoop a heaping 1/4 cup of risotto and shape into balls.
Roll ball in egg white and then in bread crumbs. Press gently to adhere breadcrumbs. Repeat with remaining risotto.
Fry balls until deep golden brown all around, about 6-7 mins. Transfer to a plate lined with paper towel to drain. Serve hot with warm marinara sauce.