1) Place stock in a medium saucepan, reserving 60ml, and bring to a simmer.
2) Meanwhile, place remaining 60ml stock and the rehydrated ancho chillies in a blender and puree until combined.
3) To the pot, add pureed chillies, porcini and hominy, and cook for 10 minutes. Add the chicken and coriander and cook for five minutes. Season with salt and pepper, to taste.
Ladle soup into bowls and top with cheese and some fried tortillas.
Rich chicken stock;
1) Preheat oven to 220°C / gas mark 8.
2) Combine chicken bones, onions, celery and carrots in a large roasting pan; toss with oil and season lightly with salt and pepper. Roast until the bones and vegetables are a rich golden brown, about 30 to 40 minutes.
3) Transfer the bones and vegetables to a large stockpot, add 2.85 litres cold water and the remaining ingredients, and bring to a boil over high heat. Reduce the heat to medium and simmer for four hours, skimming the scum that rises to the top with a ladle every 20 minutes. Remove from the heat and strain through a mesh strainer into a clean pot. Place back on the stove over high heat and cook until reduced by half.
Use immediately or let cool to room temperature, cover, and refrigerate or freeze until ready to use.
Makes about 1.5L
Heat oil in a high sided large saute pan until it reaches 180°C. Add the tortillas in two batches and cook until just crisp. Transfer to a plate lined with paper towels and season with salt immediately.