Adjust rack to top position (top and middle positions for 4 servings) and preheat oven to 425 degrees. Wash and dry produce.

Trim, peel, and cut parsnips on a diagonal into ½-inch pieces. Trim, peel, and cut carrots on a diagonal into ½-inch pieces. Cut potatoes into ½-inch-thick wedges. Halve, peel, and cut half the onion into ½-inch wedges (you'll finish prepping the remaining onion in Step 4).

Cut broccoli into bite-size pieces if necessary.

Toss parsnips, carrots, potatoes, and onion wedges on one side of a baking sheet with a drizzle of oil, salt, and pepper (for 4 servings, spread veggies out across entire sheet). TIP: Line sheet with foil first for easier cleanup! 

Roast on top rack for 10 minutes (you'll add more to the sheet then).

Swap in broccoli for carrots. 

While veggies roast, in a large bowl, combine beef*, panko, ketchup, garlic powder, 1 tsp salt (2 tsp for 4 servings), and pepper. 

Form mixture into two 1-inch-tall loaves (four loaves for 4).

Once veggies have roasted 10 minutes, remove sheet from oven. Carefully place meatloaves on opposite side of sheet (for 4, leave veggies roasting; place meatloaves on a second baking sheet). Return to top rack and roast until veggies are browned and tender and meatloaves are cooked through, 17-20 minutes. (For 4, roast meatloaves on middle rack, swapping rack positions with veggies halfway through.)

Meanwhile, finely dice remaining onion.

Melt 1 TBSP butter (2 TBSP for 4 servings) in a medium pan over medium heat. Add diced onion and 1 tsp sugar (2 tsp for 4); season with salt. Cook, stirring occasionally, until lightly browned and softened, 7-9 minutes. TIP: If onion begins to brown too quickly, lower heat and add a splash of water.

Sprinkle flour over onion mixture; cook, whisking constantly, until flour is lightly browned, 1-2 minutes. 

Slowly whisk 1 cup water (1½ cups for 4 servings) and stock concentrate into pan. Cook, whisking constantly, until thickened, 3-5 minutes.

Remove from heat; whisk in sour cream. Taste and season with salt and pepper. TIP: If gravy seems too thick, whisk in a splash of water.

Divide meatloaves and veggies between plates in separate sections. Top meatloaves with gravy and serve.