Heat oil in a large nonstick skillet over medium heat until shimmering. Cook onion and 1/4 tsp salt until softened, about 8 mins. Add mushrooms and cook until they release their liquid, about 5 mins. Increase heat to medium-high and cook until liquid has evaporated, about 5 mins. Add garlic and thyme and cook until fragrant, about 30 seconds. Stirin in tomato juice and cook until thickened, about 1 min. Let mixture cook 5 minutes then transfer to a food processor, add bread and process until smooth. Add beef to food processor and pulse to combine.
Whisk egg, soy sauce, mustard, parsley, 1/4 tsp salt, and 1/2 tsp pepper in large bowl. Add beef mixture and mix with hands until evenly combined. Using hands, shpe mixture into loaf 8” x 6”.
For Glaze: Combine ketchup, vinegar, hot sauce, and sugar in a small saucepan. Simmer over medium heat until thick and syrupy, about 5 mins.
To Freeze: Freeze in freezer safe container, freezing glaze separate.
To Reheat: Heat oven to 375 degrees. Set a wire rack inside a cookie sheet. Place aluminum foil (8”x6”) on center of rack and poke holes with a skewer at 1/2” intervals. Bake for 60 mins or until 160 on thermometer. Spread glaze over meatloaf and broil until glaze starts to bubble, about 3 mins. Let rest 10 mins. Serve.