2) Put the oiled corn on a baking sheet and sprinkle it with salt and pepper. Put the oiled tomatoes on another baking sheet and bake them both for 10 to 12 minutes until the tomato skin blisters and the corn is lightly browned.
3) In a grill pan, grill the red capsicum under a medium-high heat until it is black on each side. Put the tomatoes and the capsicum in the refrigerator, and peel them when they have cooled.
4) Heat the butter in a large pan over medium heat and add the onion and garlic and saute. Stir in the flour and cook for 2 to 3 minutes. Add the chicken stock, roasted corn, peeled tomatoes, single cream, and 250g of the tortilla chip pieces and mix well.
5) Pour the mixture into a food processor or blender and puree until smooth.
6) Strain the chowder and season it with cumin, chili powder, salt, and pepper, to taste.
7) Peel and dice the red pepper. Serve the soup topped with diced avocado, red capsicum, and the remaining tortilla chip pieces. Serve immediately.
Cooks note: When blending hot liquids: Remove liquid from the heat and allow to cool for at least 5 minutes. Transfer liquid to a blender or food processor and fill it no more than halfway. If using a blender, release one corner of the lid. This prevents the vacuum effect that creates heat explosions. Place a towel over the top of the machine, mix a few times then process on high speed until smooth.