Lancashire hotpot

Name: Lancashire hotpot
Prep time: 30 min
Total time: 30 min
Cuisine: European, British
Ingredients: 1kg King Edward potatoes, sliced horizontally (roughly 2mm thick); 40 g melted salted butter, plus a little extra for greasing; 30 g plain flour; 1 tsp. fresh thyme, chopped; 1kg diced lamb, we used neck and shoulder fillet; 1 bay leaf; 3 onions, thinly sliced; 500 mL chicken stock (we used fresh but stock cubes are fine); 125 g Lancashire cheese, grated (Cheddar works too); 2 tsp. salt; White pepper