Break up the ground beef in a medium mixing bowl. In a small cup combine the baking soda with 2 tablespoons water, ½ teaspoon salt and ¼ teaspoon pepper. Stir to dissolve. Pour the baking soda mixture over the ground beef and toss it all to combine. Set the meat aside for 20 minutes at room temperature.

In a large skillet add the butter and olive oil. Heat over medium until butter is melted and just starting to foam. Add the onion, leek, celery, carrots, ½ teaspoon salt, ¼ teaspoon pepper and paprika, if using. Cook, stirring occasionally, until the celery and carrots start to soften, about 7 minutes.

Add the minced garlic and tomato paste and stir constantly until the mixture darkens and the garlic is fragrant, about 2 minutes.

Sprinkle the flour over the vegetables and stir to combine. Cook, stirring constantly for about 2 minutes, scraping up the browned bits on the bottom of the skillet.

Add the beef broth, Worcestershire sauce, parsley, rosemary and thyme. Scrape the bottom of the pan to release any browned bits and bring to a boil, still over medium heat.

Reduce the heat to medium-low and spread out the vegetables evenly. Add the beef in small portions on top of the vegetables. Bring the mixture to a simmer, cover and cook until the beef is cooked through, about 12-15 minutes, stirring regularly.

Whisk together the cornstarch with 1 tablespoon water and add it to the beef. Cook for 1 minute or until slightly thickened. Stir in the peas and remove the skillet from the heat. Check the seasoning and add salt and pepper as needed.

Pre-heat the oven to 425F.

Using a fork, pierce steam holes evenly over each potato. Rub with a little olive oil and sprinkle with salt.

Place the potatoes directly onto a rack set in the centre of the oven. Bake for 50-60 minutes, until a knife slides in easily.

Remove and cool till you can handle them. Slice off the top section to expose enough of the interior to scoop it all out.

Scoop out the filling, leaving a wall of flesh around the exterior to maintain structure when filled. Leave around ⅙ inch but no more than ¼ inch of 'wall'.

Add the scooped out filling into a bowl. Add the butter, milk (start with less), salt, pepper (start with less), nutmeg and cheddar cheese. Blend with a fork till rustically smooth.

Taste and re-season as desired.

Place all the hollowed out potatoes onto a baking sheet. Spoon in the filling, packing it in without pressing too hard. Fill it right to the top.

Divide the mashed potato mixture between the potatoes. Fluff the tops lightly with a fork, creating a pattern for browning.

Sprinkle with more cheese and chili flakes if desired.

Bake until the cheeses have melted, starting to bubble, and the filling is warmed through, about 20-25 minutes.

Sprinkle with chopped parsley or chives, and more chili flakes if you want.

Serve with a side salad or roasted or steamed broccoli.