Combine the meat, breadcrumbs, onion, carrots, garlic, celery, parsley, egg, 1/4 cup of the half-and-half, and 1/4 cup seltzer water until just mixed. Be careful to not over work the mixture.
Form into a loaf, place it in a baking dish, then completely cover the loaf with overlapping strips of bacon.
Preheat oven to 425°F Put the meatloaf in the preheated oven for about 20 minutes to crisp up the bacon, then reduce the heat to 325F.Combine the milk and the beef bouillon, then pour it into the pan around the loaf. Cook for 30 more minutes.
To make gravy, pour the pan liquid into a saucepan along with the remaining 1/4 cup half-and-half; turn the heat on medium and bring to a simmer. Whisk together the flour and water, then stir it into the pan; continue to stir until the gravy thickens. Whisk in the rhubarb jam and Kitchen Bouquet. Once the jam has melted, transfer to a gravy boat.
Slice the meatloaf and serve with the gravy, potatoes or noodles,.