Fill a large pan with water. Add a large pinch of salt. Cover and put on a high heat to come to the boil. Preheat your oven to 200°C/Fan 180°C/Gas 6.

Scrub and peel the potatoes. Chop them into roughly equal-sized chunks, around 3-4cm across. Pop them in a large colander and rinse them under cold water to get rid of some of the starch. When the water in the pan is boiling, add the potatoes. Bring back to a gentle simmer, and then simmer for 6-7 mins till just tender.

Drain the potatoes, then gently shake the potatoes to rough up the edges (this will help them crisp up in the oven). Lay a clean tea towel on your kitchen surface and tip the potatoes out onto them. Spread the potatoes out and let them steam-dry for 5-10 mins.

While the potatoes simmer and dry, slice the beef dripping in half and divide between 2 large roasting tins. Pop the roasting tins into the oven to heat for 10-15 min till the beef dripping has melted and is glistening.

Take the tins out of the oven and add the potatoes. Turn them a few times to coat in the hot dripping. Make sure the potatoes aren't too crowded in the tin – it's better to use two tins and give the spuds room to roast, rather than cramming them in so they end up steaming. Roast for 40-50 mins, turning them once or twice, till they’re golden brown all over. Open the oven door every 15 mins briefly to let out any steam.

While the potatoes roast, pick the rosemary leaves off the woody stalks and finely chop the leaves. Peel the garlic cloves, leaving them whole. When the potatoes have 5 mins mins remaining, remove the roasting tin from the oven and scatter over the rosemary and garlic cloves. Return the potatoes to the oven for a further 5 mins,

When the potatoes are crisp and golden brown, remove from the oven. Lift them out of the tin with a slotted spoon and transfer to a bowl. Sprinkle over some seasalt and serve.