Cut the liver and hearts lengthwise into ½in/1cm thick strips, and cut the kidneys into 1in/2.5cm cubes.
In a large sauté pan, heat the oil over medium-high heat and add the liver, hearts, and kidneys. Sauté for 2 minutes. Add the onions and garlic, and sauté for 3 to 5 minutes until browned.
Add the potatoes, salt, pepper, and thyme, and sauté for 2