Heat 2 tablespoons of oil in a large saucepan over medium heat. Add 1 diced onion and sauté until translucent, about 5 minutes. Stir in 2 minced garlic cloves and 1 teaspoon of thyme, cooking for an additional 1-2 minutes until fragrant.

Pour in 4 cups of broth and 1 cup of apple cider, stirring to combine. Add 2 cups of diced apples and bring to a boil. Reduce the heat and let it simmer uncovered for about 20 minutes, or until the apples are tender.

Stir in 1 teaspoon of vanilla extract and ¼ cup of maple syrup. Gradually add 1 cup of aged cheddar and 8 ounces of brie, stirring until the cheeses have melted and the soup is creamy, about 5 minutes.

Using an immersion blender, puree the soup until smooth. Season with salt and pepper to taste.

Preheat your oven to 375°F. In a mixing bowl, combine ¼ cup of melted unsalted butter, ½ cup of flour, and ½ cup of brown sugar. Mix in 1 cup of oats and ½ cup of chopped walnuts. Spread on a baking sheet and bake for 10-20 minutes, stirring occasionally until golden brown.

Ladle the soup into bowls and sprinkle the baked granola topping over each serving.