Preheat the oven to 425°F (220°C) and line a baking sheet with parchment paper.

Roughly chop the red bell pepper, 1/2 medium onion, seeded jalapeño pepper, and fresh parsley.

Process the chopped vegetables and parsley in a food processor until they form a fine herb mixture.

Transfer the herb mixture to a fine-mesh sieve and squeeze out as much excess liquid as possible.

Combine the 2 lb ground beef with the squeezed herb mixture in a large mixing bowl.

Add black pepper, ground cumin, paprika, mild red pepper paste, allspice, and salt to the beef mixture.

Mix the kebab mixture thoroughly by hand until evenly seasoned and cohesive.

Mix in 1 to 2 tablespoons plain yogurt only if the meat mixture feels firm or dry.

Divide the meat into 8 equal portions and shape each portion into an elongated kebab.

Arrange the kebabs on the lined baking sheet, leaving space between each kebab.

Cut the onion chunks and tomatoes into large roasting pieces.

Add onion chunks, Serrano peppers, tomatoes, and red chili peppers around the kebabs on the baking sheet.

Drizzle the kebabs and vegetables with olive oil.

Bake for 20 minutes at 425°F (220°C), until the kebabs are cooked through and reach 160°F (71°C) internally.

Rest the cooked kebabs for 5 minutes, then serve hot with the roasted vegetables.