Grilled Shrimp Po' Boys: Season the shrimp with Cajun seasoning and toss with olive oil.
Heat a grill to medium heat. Grill the shrimp for a couple of minutes per side until cooked through (cook to an internal temperature of 145°F (63°C)). Alternatively, cook them on a stovetop grill pan.
Prepare the Remoulade: Whisk all the remoulade ingredients together in a bowl.
Toast the Baguette: Lightly toast the baguette on the grill.
Assemble the Sandwich: Layer the baguette with shredded lettuce, tomato slices, sliced peppers (optional), and shrimp. Drizzle with remoulade sauce.
Mango Lassi: Add mango, yogurt, milk, cardamom powder, and sugar to a blender. Blend until super smooth. Adjust sweetness and consistency by adding more sugar, milk, or mango, along with a splash of water if needed. Pour into glasses.
Serve: Plate the grilled shrimp po' boys with carrot sticks and ranch on the side. Serve alongside mango lassi.