Instructions

1. Make the risotto: In a large pot, bring the stock to a simmer; keep warm. In a second large pot, melt the butter with the olive oil over low heat. Add the shallots and garlic and cook, stirring occasionally, until softened and translucent, about 6 minutes. Turn the heat to medium-high, stir in the rice, and cook until lightly toasted and fragrant, 2–3 minutes. Add one third of the stock and simmer, stirring frequently, until nearly absorbed, 5–7 minutes. Repeat the process with the remaining stock in two additions, until the rice is tender and creamy but still holds its shape and all of the stock is absorbed, 15–19 minutes total. (If the rice is tender and creamy before all the stock has been added, reserve the remaining stock for another use. If the liquid is fully absorbed and the rice is not yet tender and creamy, add water or additional stock ¼ cup at a time until it has reached the desired doneness.) Remove from the heat. Stir in the parmesan and season with salt to taste. Spread the risotto on two baking sheets and let cool to room temperature. Cover and refrigerate for at least 4 hours, or up to 24.
2. Meanwhile, make the meat ragù: To a large, heavy pot over medium-high heat, add the pork and veal and cook, stirring occasionally with a wooden spoon to break up the meat, until no longer pink, about 10 minutes. Transfer to a bowl and set aside.  
3. To the same pot over medium heat, add the olive oil. When it’s hot and shimmering, add the garlic, carrots, celery, and onions and cook, stirring frequently, until softened and fragrant, 8–10 minutes. Stir in the tomato paste and cook, stirring occasionally, until darkened, 2–3 minutes.
4. Add the wine, stirring and scraping up any browned bits, and bring to a simmer. Simmer until reduced by half, 4–5 minutes. Add the demi-glace and reserved meat and any juices to the pot and bring to a simmer. Turn the heat to medium-low and continue to simmer, stirring frequently, until most of the liquid has evaporated, about 1 hour. The ragù should be stiffened enough to form into small balls. Season with salt and black pepper to taste. Spread the ragù on a baking sheet and set aside to cool to room temperature, about 1 hour.
5. Preheat the oven to 425°F. To assemble the arancini, divide the risotto into 12 equal portions, about ½ cup each. Roll each portion into a ball, then use your thumb to make a deep, wide indentation in the center of each. Place 1 heaping tablespoon of the ragù filling in the center of each, then shape the risotto around the filling and form back into a smooth ball.
6. Make the breading: Add the flour to a shallow bowl, the eggs to a second shallow bowl, and the bread crumbs to a third shallow bowl. Coat each rice ball first in the flour, then in the egg, and finally in the bread crumbs.
7. To a large pot fitted with a deep-fry thermometer, add the vegetable oil and turn the heat to medium-high. When the temperature reads 350°F, add the balls in batches and fry until crisp and deep golden brown, about 4 minutes per batch. Using a slotted spoon, transfer the arancini to a paper towel-lined baking sheet to drain. Bring the oil back to temperature between each batch.
8. Transfer the arancini to a parchment-lined baking sheet and bake until heated through (the center should register 160°F), about 6 minutes. Serve the arancini warm, drizzled with olive oil and topped with extra parmesan.