Step 1

Preheat the oven to 375ºF/190ºC. Arrange a rack in the center position. Select two large rectangular baking pans - one slightly smaller than the other, so the small one can fit into the larger one.

Step 2

To make the glaze (if using) combine all the glaze ingredients in a small saucepan and whisk while heating over medium heat, for a few minutes, until the sugar is melted and all the ingredients are combined. Set the glaze aside while you prepare the meatloaf.

Step 3

Melt butter in a heavy skillet and add the onion, scallions, carrots, celery, bell peppers, and garlic. Cook, stirring often, over medium heat, until the moisture from the vegetables has evaporated, 8-10 minutes. Chill the vegetables for a half hour or so in a covered bowl in the fridge or for ten minutes in the freezer.

Step 4

Combine the salt, black pepper, white pepper, cayenne, cumin, nutmeg, and eggs in a mixing bowl, and beat well, then whisk in the ketchup and half-and-half.

Step 5

Add the beef, sausage, and bread crumbs and chilled vegetables to the egg mixture and mix with your hands for several minutes, until ingredients are smooth and throughly combined.

Step 6

Add the mixture to the smaller baking pan and shape it, with damp hands, into a long low oval that measures 13 x 6 x 1 ½ inches or  17 x 4 ½ x 1 ½ or something along those lines, so it fits into your pan.

Step 7

If glazing, spread the glaze evenly over the top and sides of the meatloaf.

Step 8

Place the smaller baking dish inside the larger pan and pour boiling water into the larger pan until it reaches halfway up the sides of the smaller baking dish. (see notes below)

Step 9

Place the pans in the oven and bake for 45 minutes to an hour, or until the meatloaf is no longer pink in the middle or the internal temperature has reached at least 160ºF when tested with a food thermometer.

Step 10

Remove the smaller baking dish from the water bath and let the meatloaf rest for 20 minutes before slicing and serving.