Start by preheating your oven to 375°F (190°C) and placing the rack in the middle. This ensures even baking and a perfectly golden, bubbling dip. While it warms, lightly grease your baking dish to prevent sticking.
Slice your baguette into ½-inch rounds. Brush both sides with olive oil, sprinkle lightly with salt, and arrange on a baking sheet. Bake for 10-15 minutes until golden and crisp—these crunchy slices are the perfect dip vehicle.
In a mixing bowl, combine softened cream cheese and Boursin cheese. Blend until smooth using a hand mixer or spatula. Add half the mozzarella, Parmesan, mayonnaise, white wine, garlic, and black pepper; mix until fully incorporated and creamy.
Spread the mixture into the prepared baking dish, then sprinkle remaining mozzarella on top. Bake for 20-25 minutes until bubbling and golden. The aroma will fill your kitchen, signaling it’s almost ready.
Let the dip rest 5-10 minutes after baking to thicken slightly and let flavors meld. Garnish with fresh herbs or extra cheese if desired. Serve warm alongside your homemade crostini for a show-stopping appetizer.