Adjust rack to top position (top and middle positions for 8 servings) and preheat oven to 425 degrees.

Heat a drizzle of oil in a small pot (medium pot for 8) over medium-high heat. Add tomato paste and cook, stirring, until darkened in color, 1-2 minutes.

Add rice, one stock concentrate (two for 8), 1¼ cups water (2¼ cups for 8), and a big pinch of salt. Bring to a boil, then cover and reduce to a low simmer. Cook until rice is tender, 15-18 minutes.

Keep covered off heat until ready to use in Step 4.

Meanwhile, wash and dry produce.

Halve bell peppers lengthwise; remove stems and seeds. Trim and thinly slice scallions, separating whites from greens; mince whites. Finely dice tomato. Roughly chop cilantro. Quarter limes. Peel and mince or grate garlic.

Place bell peppers on a baking sheet (divide between two baking sheets for 8 servings) and drizzle each half with oil; rub to coat. Season with salt and pepper. Arrange cut sides down; roast on top rack (for 8, roast on top and middle racks, swapping rack positions halfway through) until tender, 10-15 minutes.

In a small bowl, mix together scallion whites, tomato, half the cilantro, juice from four lime wedges, and a pinch of salt and pepper (for 8, use all the cilantro and juice from eight lime wedges). 

Heat a drizzle of oil in a large pan (for 8 servings, use two large pans or cook in batches) over medium-high heat. Add beef*, garlic, Mexican Spice Blend, remaining stock concentrates, salt, and pepper. Cook, breaking up meat into pieces, until browned and cooked through, 4-6 minutes.

Using a slotted spoon, transfer beef mixture to a large bowl.

Fluff rice with a fork (it’s OK if rice has a little extra liquid); transfer to bowl with beef mixture. Stir until thoroughly combined. Taste and season with salt and pepper if desired.

Once bell peppers are done roasting, remove sheet from oven. Carefully flip bell peppers and stuff each half with as much filling as will fit. Sprinkle with Mexican cheese blend.

Heat broiler to high (or increase oven temperature to 500 degrees).

Transfer stuffed peppers to top rack and broil (or roast) until cheese is melted and bubbly, 2-4 minutes (for 8 servings, broil or roast in batches). TIP: Watch carefully to avoid burning!

In a second small bowl, combine guacamole and a squeeze of lime juice; season with salt and pepper to taste.

Divide stuffed peppers between plates. Top peppers with scallion greens and juice from two lime wedges (four wedges for 8 servings). (TIP: If you like things spicy, add a few dashes of hot sauce!) Place guacamole, pico de gallo, and sour cream in separate serving bowls and serve with remaining lime wedges on the side.