Wash and dry all produce. Adjust rack to middle position and preheat oven to 450 degrees. Mince or grate garlic. Grate one shallot into a large bowl. Halve, peel, and mince other shallot. Strip thyme leaves from stems; discard stems. Roughly chop leaves. Halve carrots lengthwise. Peel potatoes, then cut into thin sticks (like French fries).

Toss carrots with a large drizzle of olive oil and arrange toward one side of a baking sheet. Toss potatoes with a large drizzle of olive oil and arrange toward other side. Season both with salt and pepper. Roast in oven until tender and browned, 20-25 minutes total (we’ll add more to the sheet after 7-8 minutes).

Add panko, beef, half the thyme, garlic, and a few dashes of salt and pepper to bowl with grated shallot (we used 3/4 tsp kosher salt). Gently combine with hands, then shape mixture into four 1-inch-tall loaves.

After veggies have roasted 7-8 minutes, remove sheet from oven. Give veggies a toss. Place meatloaves on same sheet, then brush tops of loaves with ketchup. Return sheet to oven and continue roasting until meatloaves are cooked through, 15-18 minutes more. TIP: If there isn’t enough room on your sheet, you can add the meatloaves to a second sheet.

Melt 1 TBSP butter in a medium pan over medium heat. Add minced shallot and remaining thyme. Cook, tossing, until softened, 3-4 minutes. Sprinkle flour into pan, stirring vigorously to combine. Whisk in stock concentrates and 1 cup water. Bring to a simmer and let bubble until thick and saucy, 3-4 minutes. Season with salt and pepper.

Slice meatloaves crosswise and divide between plates. Arrange veggies to the side. Spoon gravy over meatloaves and serve.