• Adjust racks to top and middle positions and preheat oven to 450 degrees. Bring 1 TBSP butter (2 TBSP for 4 servings) to room temperature. Wash and dry produce. • Cut potatoes into 1/2-inch-thick wedges. Halve, peel, and finely dice half the onion (whole onion for 4). Halve baguettes lengthwise, stopping before you get all the way through.

• Lightly oil a baking sheet. Toss potatoes on one side of prepared sheet (whole sheet for 4 servings) with a drizzle of oil, salt, and pepper. • Roast on top rack for 5 minutes. (You’ll add more to the sheet then.)

• Meanwhile, in a medium bowl, combine beef*, panko, 2 tsp Italian Seasoning (4 tsp for 4 servings), salt (we used 1/2 tsp; 1 tsp for 4), and pepper. Form into 6 equal-size meatballs (12 for 4). • Once potatoes have roasted 5 minutes, remove sheet from oven. Carefully add meatballs to empty side. (For 4, leave potatoes roasting; add meatballs to a second sheet and roast on middle rack.) Return to top rack, tossing halfway through, until everything is browned and cooked through, 18-20 minutes more.

• Meanwhile, heat a drizzle of oil in a large pan over medium heat. Add onion; season with a pinch of salt and pepper. Cook, stirring occasionally, until browned and tender, 5-7 minutes. • Add tomato paste and remaining Italian Seasoning. Cook, stirring constantly, until fragrant and darkened, 30-60 seconds. TIP: If you like things spicy, add a pinch of chili flakes from your pantry. • Add marinara, stock concentrate, 1/2 cup water (3/4 cup for 4 servings), and a pinch of sugar. Cook, stirring occasionally, until thickened, 2-3 minutes. • Remove from heat; season with salt and pepper.

• Once potatoes and meatballs are done, remove sheet from oven. • Toast baguettes, cut sides up, directly on middle rack until golden, 2-3 minutes. • Spread softened butter onto cut sides of baguettes and season with a pinch of salt and pepper

• Transfer meatballs to pan with sauce; gently turn to coat. • Place toasted baguettes on sheet with potato wedges. (For 4 servings, place baguettes on sheet used for meatballs.) Fill baguettes with meatballs and sauce; sprinkle tops with mozzarella. Return to top rack until cheese melts, 2-3 minutes. • Divide meatball subs and potato wedges between plates. Serve.