Make the cream cheese mix. Heat your oven to 200C/390F and prepare a small oven-safe baking dish or pan (I'm using a 20cm/8" pan). Add 250g/9oz cream cheese, 1/2 cup sour cream, 3 crushed garlic cloves, 1 teaspoon dried thyme, 1 teaspoon chilli flakes and 1 teaspoon salt to a small bowl, then mix to combine into a creamy, smooth sauce.
Assemble the dip. Spoon the cream cheese mixture onto the base of your prepared pan, smoothing it onto an even layer. Pour oven your pizza sauce, again smoothing it to an even layer. Scatter over your grated mozzarella, cheddar and parmesan, then finish with your pepperoni slices.
Bake the dip. Transfer to the oven and bake for 25 minutes, or until the cheese is molten and charred, the pizza sauce is bubbling up around the edges and the pepperoni is crispy. You can pop it under your broiler/grill for a couple of minutes too if you like.
Garnish and serve. Carefully remove the pan from the oven, then drizzle over 2 tablespoons of sweet chilli jam and scatter with the fresh basil leaves. Serve right away, while hot and oozy.