Preheat the oven to 375°F. Grease a 9-inch ceramic pie plate.
Put the ground beef and 1 3/4 teaspoons sea salt in a large heavy skillet over medium heat. Cook for 8 to 10 minutes, breaking the meat into small crumbles, until no pink remains and most loose liquid has cooked away. If the skillet is crowded enough to steam the beef, cook it in two batches.
During the final 2 minutes, add the dill, mint, rosemary and 1 teaspoon powdered ginger. Stir until the dried herbs are fragrant and evenly distributed through the beef.
Transfer the cooked beef to the greased pie plate and press it into a level layer without packing it hard.
While the beef cooks, steam the chopped carrots until the thickest piece crushes immediately under a fork. Let them cool just until excess steam is no longer billowing.
Puree the carrots in a food processor or mash them thoroughly by hand until smooth and thick enough to hold a soft ridge.
Mix the lemon juice, 1/2 teaspoon dried ginger, 1/4 teaspoon sea salt and pure bicarbonate of soda into the carrots until evenly combined.
Spread the carrot mixture over the beef in an even layer all the way to the edge. Leave broad shallow swirls across the top.
Bake at 375°F for about 40 minutes, until the topping looks set instead of wet, the outer edge is browned and a few shallow cracks may appear. The starch-free topping may not puff like a tapioca-thickened version.
Rest the pie for 10 to 15 minutes before cutting 6 wedges. The source also allows a longer rest, up to 1 hour, before serving.