Prepare the Meatball Mixture: In a large mixing bowl, combine the minced beef, finely diced onion, minced garlic, fresh breadcrumbs, egg, Dijon mustard, salt, white pepper, and nutmeg. Use your hands to gently mix everything together until it just comes together. Overmixing will make the meatballs tough. You should feel a cohesive, slightly sticky texture that holds its shape when pressed.

Shape the Meatballs: With slightly damp hands to prevent sticking, roll the mixture into golf ball-sized portions. Aim for about 24 meatballs. As you roll them, you want to see a smooth, even surface with no cracks. Place them on a tray lined with baking paper and chill in the fridge for at least 20 minutes. This firms up the fat and helps the meatballs hold their shape during frying.

Create the Crisp: Heat the vegetable oil in a large, heavy-bottomed frying pan over a medium-high heat. The oil should shimmer and a breadcrumb dropped in should sizzle immediately. Carefully place the chilled meatballs in a single layer, making sure not to overcrowd the pan. Fry for 3-4 minutes per side, turning gently with a spatula. You are looking for a deep, golden-brown crust that is firm to the touch. The sizzle will become quieter as the crust forms. Work in batches, keeping the cooked meatballs warm in a low oven.

Build the Sauce Base: Once all the meatballs are fried and resting, reduce the heat to medium. Add the butter to the pan and let it melt, scraping up any browned bits from the bottom of the pan with a wooden spoon. These browned bits are packed with flavour. You will see the butter foam and then subside.

Make the Roux: Sprinkle the plain flour into the melted butter and whisk continuously for 1-2 minutes. The mixture will bubble and turn a pale, biscuit colour. You are looking for a smooth, thick paste that smells slightly nutty. This step is crucial for a sauce with a silky, not lumpy, texture.

Simmer the Sauce: Slowly pour in the beef stock, whisking constantly to prevent lumps from forming. The mixture will thicken immediately. Bring it to a gentle simmer, and you will see small bubbles break the surface. Cook for 3-4 minutes, allowing the sauce to reduce slightly and intensify in flavour. The sauce should coat the back of a spoon.

Finish the Sauce and Meatballs: Reduce the heat to low and stir in the double cream, chopped capers, and lemon juice. The sauce will turn a beautiful, pale ivory colour and have a glossy sheen. Taste and adjust the seasoning with salt and white pepper. Gently return the fried meatballs to the pan, spooning the sauce over them. Simmer for 3-4 minutes until the meatballs are heated through and the sauce has thickened to your liking. The meatballs should be glistening and nestled in a rich, creamy sauce.