Melt the bitter in a large frying pan over medium heat. Add the onions with a pink of salt and cook until soft, stirring occasionally, allowing them to start to caramelise.

Add the thyme and cook for 1-2 minutes until fragrant. Remove from heat and set aside.

In a large bowl, smash the butterbeans with a potato masher or sturdy fork.

Add the grated Dubliner Mature White, mustard powder and cooked onion mixture and mix well to combine. Season to taste with salt and pepper.

Pre-heat oven to 200°C / 180°C fan / gas 6 and line 2 large trays with parchment paper.

Unroll the puff pastry and loosen it from the paper it’s rolled in. Lay it back on the paper, longest edge closest to you. Use a pizza wheel or large sharp knife to divide both sheets into 2 lengthways.

Spoon ¼ of the butterbean mixture in the centre and along the length of each strip of puff pastry. Use your hands to press and compact the filling in a sausage shape.

Fold the pastry over the filling then press the tines of a fork all along the edges to seal in the filling.

Use a sharp knife to cut each long sausage roll into 4, then transfer each to the lined baking trays.