Heat your oven to 180°C/Fan 160°C/Gas 4. Peel and thinly slice the onion and garlic cloves. Slice the potatoes as thinly as possible. Dissolve the stock cube in 200ml boiling water.
Brush a baking dish with 1 tbsp olive oil. Lay the potatoes, onion and garlic in the dish, alternating the layers and seasoning as you go. Finish with a layer of the potatoes.
Pour the stock over the top and place in the oven for 40 mins till the top is crispy and the lower layers are soft.
While the potatoes are cooking, make your pea purée. Pop the peas out of their pods. Place the peas in a small pan and pour over enough boiling water to cover them. Simmer for 2 mins. Drain and refresh under cold water.
Tip the cooled drained peas into a food processor with the dill. Season. Blitz for 1 min till you have a smooth purée. No processor? Mash the peas with a fork or masher - less smooth but still full of flavour.
Heat a frying pan or griddle pan. Rub each lamb chop with ½ tsp olive oil and seasoning. Place in the hot pan and cook for 4 mins on each side. Cook for an additional 1-2 mins each side for a well done chop.
Place the chops on a baking tray lined with baking paper. Dollop 1 tbsp of pea purée onto each chop and smooth out with the back of your spoon to cover the chop. Pop into the oven and bake for 5 mins. Serve the chops with the potatoes and the left over pea purée.