Prepare the ingredients as instructed above.
Make split pea soup: Add split peas, onion, carrot, celery, garlic, broth, thyme, black pepper, and bay leaf to a slow cooker. Cover and cook on low for 8 hours, until peas are tender. Season with salt and pepper. Remove bay leaf before serving.
Prepare panini spread: Mix mayonnaise and pesto in a small bowl. Spread on one side of each bread slice.
Assemble panini: Layer mozzarella (drizzled with olive oil), basil leaves, and tomato slices (seasoned with salt and pepper) on bread. Top with another slice.
Grill panini: Spray panini press or skillet with nonstick spray. Grill until bread is golden and cheese is melted. If using a skillet, press with a lid and cook both sides until melty.
Make mango lassi: Blend mango, yogurt, milk, sugar, and cardamom until smooth. Adjust sweetness or consistency with extra sugar, milk, water, or mango. Chill until ready to serve.
Serve the split pea soup with caprese panini and mango lassi.