Place a pan on the stovetop and add 2 tbsp of butter to the pan. Allow the butter to melt then add the chopped lamb into it. Cut the lamb into very small sizes.
Fry the lamb or mutton until it is brown
Once the fried mutton is golden brown in color, shift it to one side of the pan and add the sliced onions and the chopped carrots; stir fry until the onions are fragrant and translucent.
Season with salt and black pepper, about 1/4 tsp each; then stir to combine.
Sprinkle some plain flour over it and cook until the raw flavour of the flour is gone. The flour helps to thicken the Lancashire hotpot. You can also use cornstarch or any type of flour that you often used as a thickener for soups and stews.
Add 500 ml of lamb stock, Worcestershire sauce, and bay leaves; stir to combine.
Cover and cook for 15 minutes while preparing the Russet potatoes. Ensure you peel the potatoes and rinse with clean water.
Now, cut the potatoes into thin slices of about 2 or 3 mm. You can use a Mandolin slicer to ensure you have very thin cuts of potatoes that become soft easily when cooked in the oven; cutting larger chunks of potatoes makes them crunchy even after cooking for an hour in the oven. Keep aside and wait for the lamb stew to cook for 15 minutes.
After 15 minutes, turn off the heat and pour the mutton stew into a casserole.
Arrange the sliced potatoes over it the stew in the casserole and brush their surface with some melted butter.
Sprinkle some salt, thyme, and black pepper.
Cover with foil paper; now, bake for 1 hour. If your casserole is shallow and wider, the potatoes cook in time, but if it is narrow and deep, the potatoes take longer for heat to penetrate under.
After an hour of baking the Lancashire hotpot, remove the foil paper and continue cooking it in the oven for another 30 minutes until the potatoes are brown and crispy. Your easy Lancashire hotpot recipe is ready.