Whisk the psyllium husk powder into the flour in a medium bowl until one color.

Cut in the coconut oil with a pastry cutter, fork, or two knives cross-wise. The oil should get evenly distributed and the mixture will look a bit like sand when you're done, with no big chunks of oil visible.

Stir in the milk with a spatula, mixing until everything is incorporated. Knead a few times to pick up all the stray flour until you have a smooth ball of dough. Set aside to rest.

Cook the bacon in a large pan over medium heat until crispy, turning often. Remove to a paper-towel-lined plate. Drain all but 2 tbsp of the rendered bacon fat from the pan. (I store rendered bacon fat in a heavy glass jar in the refrigerator and use it for cooking eggs, greens, or other food that can use the bacon flavor. Yes, there are days when I can't believe it's my fridge.)

Peel and thinly slice the shallots. Sauté shallots in the rendered bacon fat over medium to medium-low heat about 10 minutes until golden brown.

Peel, rinse, and cut potatoes into uniform chunks. Add to a medium saucepan filled with cold water. Bring to a boil and cook for 12 minutes once boiling or until fork-tender. Drain well, spreading in a colander to continue steaming for 10 minutes.

Mash the potatoes with a fork, potato ricer, or food mill in a large bowl, adding in the milk or cream until fluffy. Do not overwork. DO NOT PUT THE POTATOES IN THE FOOD PROCESSOR.

Preheat the oven 375F/190C/gas mark 5.

Roll out the crust between two sheets of waxed paper to a rectangle or square a bit larger than your pan. I use a square steel tart pan with a removable bottom, but a regular pie pan will also work.

Peel off the top sheet of waxed paper and gently transfer the crust into the pan. Peel off the remaining waxed paper. It will tear, don't worry. Patch any holes, and make the crust as even as possible on all four sides, cutting away any excess as needed.

Beat the eggs in a small bowl.

Fold the eggs, shallots, half the crumbled bacon, and spices into the potatoes, using a spatula to mix gently.

Spread into the crust evenly. Crumble the remaining bacon evenly over the filling, pressing it gently into the surface.

Bake for 30-35 minutes until golden brown and firm in the center. Cool on a wire rack for 10-15 minutes before slicing, so it is firmed up well.