Welsh rarebit galette recipe | Sainsbury`s Magazine

Ingredients

• 125g unsalted butter
• 200g plain flour, plus extra to dust
• 1 tbsp English mustard powder
• 1⁄2 tsp fine sea salt
• 1 medium egg, separated (reserve the egg white to glaze)
• 3 tbsp olive oil
• 1 large leek (about 260g), trimmed, halved lengthways, rinsed and sliced
• 1 tbsp fresh thyme leaves, plus sprigs to garnish
• 15g butter
• 1 tbsp plain flour
• 1⁄2 tsp made English mustard
• a splash of Worcestershire sauce* or Henderson’s Relish
• 85ml brown ale*
• 90g extra mature cheddar* (we used Welsh)
• 1 large baking potato (about 350g), peeled and thinly sliced
• 1 medium egg white