Preheat oven to 350 °F and lightly grease an 8-loaf mini loaf tin.
Pulse onion and mushrooms in a food processor until fine and evenly blended. Heat a sauté pan over medium-high heat and add oil. Add mushroom mixture and cook, stirring often, until all liquid has evaporated. Add garlic and thyme and stir one minute more. Add red wine and cook until liquid again has evaporated. Season to taste and set aside to cool.
Stir breadcrumbs and crushed tomato in a small bowl and set aside. In a large bowl, blend beef and pork with eggs, salt and pepper. Add tomato-soaked breadcrumbs to meat and stir in, then stir in cooled mushroom mixture.
Spoon meatloaf filling into prepared tin and bake for about 40 minutes, until an internal temperature of 170 °F is reached and serve with your favourite condiments.
Alternatively, meatloaf recipe can be prepared in a 9-x-5-inch loaf pan and baked for about an hour.
For the mashed potatoes:
Peel potatoes and cut into 1-inch cubes. Place potatoes into cold, salted water and bring up to a boil, boiling, uncovered, until potatoes are tender, about 15 minutes. Drain well, then cover to keep warm. Return pot to low heat and melt butter. Using a ricer, press potatoes into pot and stir. Stir in buttermilk and sour cream just until warmed and season to taste. Stir in green onions immediately before serving.