Cook the diced potatoes in a large pot of boiling salted water until tender. Drain and mash. Set aside to cool.
Pour the rice into a medium size pot and add 3 cups water. Bring to the boil, stirring every now and then, cover and reduce heat and simmer until the rice is cooked and the liquid is absorbed. Set aside to cool.
Heat the olive oil in a medium fry-pan on medium-high heat. Add the bacon and onion and cook until bacon is starting the crisp and onion is translucent. Add the garlic and cook for a further minute, stirring often. Remove from the heat and set aside to cool.
Combined the cooled mashed potato, rice and onion/bacon mixture in a large bowl. Add 1/2 cup of the breadcrumbs, 1/2 cup of the parmesan cheese, beaten eggs and 1 tbsp salt. Mix thoroughly to combine (I find using hands the easiest way to mix through). Cover and refrigerate for 30 minutes.
In a medium sized bowl, combine the remaining breadcrumbs with the remaining parmesan cheese
Form the potato mixture into oblong shapes, around 6cm long and 3cm wide. Roll them into the breadcrumb mixture to coat, set aside in a single layer until ready to cook. At this stage they can be refrigerated for 1 day.
Pour enough oil in a deep saucepan to reach halfway up the sides, or use a deep fryer if you have one. Heat oil until it reaches 180 C. Cook the croquette in batches, turning every now and then, until deep golden in colour. Drain on paper towels before serving.
