Preheat the oven to 375°F. Grease the inside of an 8×8 inch baking dish.
In a large bowl, mix together the fontina, white cheddar, and Gruyère cheese.
Add the cream cheese, sour cream, and mayonnaise to the bowl and stir until the ingredients are fully combined.
Stir in the minced garlic, thyme, garlic powder, onion powder, pepper, and salt.
Transfer the cheese mixture to a greased oven safe dish, using the back of a spoon or a spatula to spread and smooth the dip out into the dish.
Bake the cheese dip for 20 to 25 minutes, or until the top of the dip is golden and bubbly.
Serve baked cheese dip warm with sliced toasted bread, crackers, dip, or sliced fresh vegetables for dipping.