Lightly season the steak with salt and pepper. Heat the oil in a large, heavy-based saucepan over medium–high heat. If using a Dutch oven or cast-iron pot, heat the oil over medium–low heat. Working in batches if needed, sear the steak on all sides until well browned and a deep crust forms. Once done, return all the beef to the pan.
Add the garlic and onion to the saucepan with the beef and stir-fry for about 1 minute until fragrant. Pour in the beef stock, then add the tomato paste, paprika, stock cube, bay leaves, salt and pepper. Stir well to combine. Bring the mixture to a boil, then cover with a lid. Reduce the heat to low and simmer gently for 1 hour and 15 minutes.
Add the potatoes to the stew, ensuring they are mostly submerged in the broth. Cover and cook for a further 20–30 minutes, or until both the potatoes and steak are tender. To test, transfer a piece of beef and potato to a small plate. If the potato pierces easily with a fork and the beef shreds effortlessly, the stew is ready.
In a small bowl, whisk together the cream and cornflour until smooth, then pour it into the stew. Stir gently to combine and cook uncovered for 10 minutes, or until the stew has thickened. Taste and adjust with additional salt or pepper if needed.