Prepare the Beef: Lay your beef steaks between two sheets of cling film. Using a meat mallet or a rolling pin, pound them gently until they are uniformly thin, about 0.5 cm thick. They should feel pliable and slightly larger. Season both sides generously with salt and black pepper.

Make the Filling: Heat 2 tablespoons of olive oil in a large frying pan over a medium heat. Add the finely chopped onion and sauté for about 5-7 minutes until it turns translucent and softens, releasing a sweet aroma. Stir in the minced garlic and chopped mushrooms, cooking for another 8-10 minutes until the mushrooms have released their liquid and taken on a lovely golden-brown colour. Remove from the heat and let it cool slightly.

Combine the Filling Ingredients: In a mixing bowl, combine the cooled mushroom mixture, wilted and squeezed spinach, breadcrumbs, chopped parsley, rosemary, and thyme. Add the lightly beaten egg and mix thoroughly until all ingredients are well combined and the mixture feels cohesive. This is a crucial step for a filling that holds together beautifully. I stumbled upon this combination by accident one evening, and it's been a hit ever since, offering a lovely earthy and herbaceous counterpoint to the rich beef.

Assemble the Roulade: Lay one prepared beef steak flat on a clean surface. Spread half of the filling evenly over the entire surface, leaving a 2 cm border on one long edge. Carefully roll the beef tightly from the opposite long edge, ensuring the filling stays tucked inside. Repeat with the second steak and remaining filling. Secure each rolled roulade with kitchen twine at 3-4 cm intervals, so they resemble neat parcels.

Sear the Roulade: Heat a tablespoon of olive oil in a large, oven-safe frying pan over a medium-high heat until it shimmers. Carefully place the beef roulades in the hot pan and sear on all sides for 8-10 minutes in total, turning regularly, until they develop a beautiful golden-brown crust. This caramelisation adds incredible depth of flavour. Remove the roulades from the pan and set aside.

Prepare the Gravy and Braise: Reduce the heat to medium. Add the plain flour to the pan drippings and cook, stirring constantly, for 1-2 minutes until it forms a light brown roux and smells slightly nutty. Stir in the tomato purée, then gradually whisk in the beef stock, scraping up any browned bits from the bottom of the pan. Bring to a simmer, then add the bay leaf. Return the seared roulades to the pan, ensuring they are partially submerged in the liquid. Bring back to a gentle simmer, then cover the pan tightly with a lid or foil.

Slow Cook: Transfer the covered pan to a preheated oven at 160°C (140°C fan/Gas Mark 3) and braise for 2 hours 30 minutes to 3 hours, or until the beef is incredibly tender and yields easily when pierced with a fork. The gravy should have thickened and deepened in colour.

Rest and Serve: Once cooked, carefully remove the roulades from the pan and place them on a cutting board. Tent loosely with foil and let them rest for 15-20 minutes. This resting period is vital for the juices to redistribute, ensuring a succulent result. While the beef rests, you can skim any excess fat from the gravy and adjust seasoning. Snip and remove the kitchen twine from the roulades, then slice each into thick, elegant rounds, revealing the vibrant spiral of filling. Serve immediately with a generous spoonful of the rich gravy.