Preheat oven to 200C/180C fan-forced. Line a baking tray with baking paper. Pat potatoes dry with paper towel. Pierce all over with a fork. Place on prepared tray. Drizzle with 1/2 the oil. Season with salt and pepper.
Roast for 1 hour 15 minutes or until golden and tender. Stand potatoes for 5 to 10 minutes or until cool enough to handle.
Meanwhile, heat remaining oil in a frying pan over medium-high heat. Add onion, carrot and celery. Cook, stirring, for 5 to 6 minutes or until just starting to soften. Add mince. Cook, breaking up mince with a wooden spoon, for 6 to 8 minutes or until browned. Add gravy powder. Stir to combine. Reduce heat to medium-low. Add stock and mint sauce. Cook, stirring, for 3 minutes or until sauce thickens. Cover to keep warm.
Cook peas following packet directions. Drain. Using a potato masher, mash peas and cream together until roughly crushed. Season with salt and pepper.
Using a small knife, cut a cross in the top of each potato. Gently squeeze the base of each potato to open top. Place on plates. Divide mince mixture among potatoes. Dollop with pea mash. Serve drizzled with gravy.
Serving size: 4
Recipe courtesy of taste.com.au