1. In a medium saucepan, heat the olive oil over medium heat. Add the chopped onion and cook until translucent, about 5 minutes. Stir in the Arborio rice and cook for an additional 2 minutes, allowing the rice to toast slightly.

2. Once the onion and rice are sautéed, stir in the chopped country ham. Gradually add the warmed chicken stock, one ladle at a time, stirring constantly until the liquid is absorbed before adding more. Continue this process until the rice is tender and creamy, about 20-25 minutes.

3. Remove the pan from the heat and stir in the grated Parmigiano-Reggiano cheese. Season with salt to taste. Spread the risotto out on a baking sheet and allow it to cool completely.

4. Once the risotto has cooled, stir in the whole egg and egg yolk. With damp hands, scoop about 2 tablespoons of the rice mixture and form it into a ball. Press a cube of mozzarella into the center, then reshape the ball to enclose the cheese. Repeat this process with the remaining rice mixture and mozzarella cubes.

5. Roll each Arancino in the plain bread crumbs until it is fully coated, ensuring a crispy exterior.

6. In a deep pot or skillet, heat the canola oil to 350°F (175°C). Carefully add the breaded Arancini in batches and fry until they are golden brown and crispy, about 3-4 minutes per batch. Transfer the fried Arancini to a paper towel-lined plate to drain any excess oil.

7. Arrange the hot, freshly fried Arancini on a serving platter. Garnish with additional grated Parmigiano-Reggiano and chopped fresh parsley. Serve these irresistible treats immediately, and enjoy the perfect balance of crispy exterior and creamy, cheesy interior in every bite.