Preheat your oven to 200°C (390°F) to get ready for baking later.
Chop or shred the leftover roast meat into small, ragged chunks, mimicking tiny spooky stones to add texture and visual interest.
In a large skillet, sauté diced onions and minced garlic until they turn translucent and fragrant, filling your kitchen with a ghostly aroma.
Add the shredded meat to the skillet, then pour in red wine or broth and stir in tomato paste, paprika, thyme, and black pepper. Cook until the mixture thickens and becomes oozy, about 5 minutes.
Stir in the frozen peas and carrots, letting them soften and release their sweet, earthy aroma into the rich gravy.
Pour the meat and vegetable mixture into a baking dish, spreading it out evenly like a secret lair of flavors.
Scoop the mashed potatoes on top, spreading them unevenly to create a lumpy, graveyard-like surface that looks spooky and rustic.
Bake the assembled shepherd’s pie in the preheated oven for 25-30 minutes, until the top turns golden brown and crackly, with some edges curling up like haunted wisps.
Remove from oven and let sit for a few minutes. The bubbling, crackly crust signals that the dish is ready to serve and enjoy.