Thaw shrimp and scallops if frozen, rinse under cold water, and pat dry.

Melt butter in a large skillet over medium heat, add chopped onion and minced garlic, and sauté for 3-4 minutes until translucent.

Fold in shrimp and scallops, sauté for about 3 minutes until shrimp is pink and scallops are opaque.

Pour in white grape juice, simmer for 2 minutes, then add heavy cream, salt, and black pepper, stirring until combined.

Transfer the seafood mixture into a greased baking dish and top with grated cheese.

Preheat oven to 180°C (350°F) and bake for about 15 minutes until cheese is bubbly and golden brown.

Remove from oven, let cool for a few minutes, and serve.