Prep all ingredients as directed above (peel and cut carrots, tear lettuce, measure seasonings, and thaw mango slightly if too hard to blend).
In a medium mixing bowl, combine the ground beef, salt, pepper, smoked paprika, BBQ sauce, and Worcestershire sauce. Mix until fully combined, then form into two patties.
Heat a grill or pan over medium-high heat. Cook the patties on both sides to your preferred doneness.
During the last minute of cooking, place a slice of cheddar cheese on each patty and let it melt.
Toast the hamburger buns on the grill or in a pan until golden brown.
Assemble the burgers: place romaine lettuce on the bottom half of each bun, top with the cooked burger patty, drizzle with additional BBQ sauce if desired, and cover with the top bun.
To make the mango lassi, blend the frozen mango, yogurt, milk, sugar, and cardamom powder until smooth. Taste and adjust sweetness if needed.
Serve the burgers alongside carrot sticks, hummus, and mango lassi.