Prep all the ingredients as described.
Make the split pea soup: In a slow cooker, combine split peas, onion, carrot, celery, garlic, chicken broth, dried thyme, black pepper, and bay leaf. Cover and cook on low for 8 hours, or until peas are tender. Season with salt and pepper to taste. Remove the bay leaf before serving.
Preheat a panini grill or skillet over medium heat.
In a bowl, mix mayonnaise and pesto. Spread onto one side of each bread slice.
Layer the panini with mozzarella (drizzled with olive oil), basil leaves, tomato slices (seasoned with salt and pepper). Top with another slice of bread.
Grill the panini: If using a panini press, spray with nonstick spray, press the sandwich, and grill until crispy and cheese is melted. (If using a skillet, place the sandwich, cover with a lid, and cook on both sides until golden and melty).
Make the mango lassi: In a blender, combine mango, yogurt, milk, sugar, and cardamom. Blend until smooth. Adjust sweetness or consistency with extra sugar, milk, water, or mango. Pour into glasses.
Serve the split pea soup with the caprese panini and mango lassi.