Place 1/2 cup stock into a 2- or 4-cup liquid measuring cup

Add 1/4 cup buttermilk to the measuring cup and stir to combine.

Sprinkle 1/2 ounce (2 packets; about 1 1/2 tablespoons) unflavored gelatin over the stock and buttermilk.

Set the stock and buttermilk aside.

Roughly chop 1 small onion (about 3/4 cup) and place in a small bowl.

Peel and roughly chop 1 carrot (about 1/2 cup) and add to the bowl with the onion.

Roughly chop 1 stalk of celery (about 1/2 cup) and add to the bowl with the onion.

Remove the crusts from 2 slices of bread, tear into rough pieces, and place in a food processor.

Clean 4 ounces of mushrooms and place into the food processor with the bread.

Pulse the bread and mushrooms until finely chopped.

Transfer the bread and mushrooms to bowl that is large enough to combine everything later.

Add 3 anchovy filets to the food processor.

Add 1/2 teaspoon of marmite to the food processor.

Add 2 teaspoons (10ml) of soy sauce to the food processor.

Add 1 teaspoon of paprika to the food processor.

Add 2 medium cloves of garlic to the food processor.

Pulse until reduced to a fine paste, scraping down the sides of the bowl.

Add the onion, carrot, and celery and to the food processor.

Pulse until finely chopped but not pureed.

Place 12 ounces of freshly ground pork into a medium bowl.

Add 1 1/4 pounds of freshly ground beef to the bowl with the ground pork.

Add 2 large eggs to the bowl with the ground meat.

Finely grate 4 ounces (about 1 cup) of cheddar, provolone, Monterey Jack, or Muenster cheese, and add to the bowl with the ground meat.

Finely mince 1/4 cup of fresh parsley and add to the bowl with the ground meat.

Add 1 tablespoon kosher salt to the bowl with the ground meat.

Grind 1 teaspoon of black pepper into the bowl with the ground meat.

Set aside 2 tablespoons of unsalted butter.

Heat the butter in a 10-inch nonstick skillet over medium-high heat until foaming.

Add the chopped vegetable mixture and cook, stirring and tossing frequently, until it is softened and most of the liquid has evaporated, about 5 minutes; the mixture should start to darken a bit.

Stir in the buttermilk mixture, bring to a simmer, and cook until reduced by half, about 10 minutes.

Transfer the vegetable and buttermilk mixture to the bowl with the mushrooms and bread.

Stir the vegetables and bread thoroughly to combine.

Let the stand until cool enough to handle, about 10 minutes.

After the vegetables and bread mixture has cooled, add the ground meat to the bowl.

With clean hands, gently mix until everything is thoroughly combined and homogeneous; it will be fairly loose.

Pull off a teaspoon-sized portion of the mixture, place it on a microwave-safe plate, and microwave it on high power until cooked through, about 15 seconds. Taste the cooked piece for seasoning and add more salt and/or pepper as desired.

Transfer the mixture to a 9- by 5-inch loaf pan, being sure that no air bubbles get trapped underneath. (You may have some extra mix, depending on the capacity of your pan; this can be cooked in a ramekin or free-form next to the loaf.)

Tear off a sheet of heavy-duty aluminum foil large enough to line a rimmed baking sheet and use it to tightly cover the meatloaf, crimping it around the edges of the pan.

Refrigerate the meatloaf for one hour or up to 2 days.

Remove the meatloaf from the refrigerator.

Remove the meatloaf from the oven and unfold the foil laying it flat.

Use a thin metal spatula to lift an edge of the inverted loaf pan, jiggling it until it slides off the meatloaf easily, and use oven mitts or a folded kitchen towel to remove the pan, leaving the meatloaf on the center of the foil.

Return the meatloaf to the oven and bake until the center of the meatloaf registers 140°F on an instant-read thermometer, about 40 minutes longer. There will be quite a bit of exuded juices; this is OK.

Remove from the oven and let rest for 15 minutes.

Increase the oven temperature to 500°F.

Use a brush to apply some glaze to the meatloaf in a thin, even layer, then return it to the oven and bake for 3 minutes.

Glaze again and bake for 3 minutes longer.

Remove from the oven and allow to rest for 15 minutes.

Slice and serve with any extra glaze and mustard or ketchup as desired.