These instructions are from the boat without benefit of a food processor. If you have a food processor, feel free to use it.
Place the dried chilies in a sauce pan and add boiling water to cover. Put on a lid and let soak for 30 minutes.
Drain the chilies and cut them open. Discard the stems and seeds.
Scrape out the flesh with a knife and set aside.
Assemble your mise en place (see photo above).
In a frying pan, heat half of the olive oil and fry the bread until golden (3 minutes per side). (When using a mortar and pestle, cut the bread into cubes to make the pounding stage a little easier.)
In a mortar, combine the fried bread, garlic, almonds, hazelnuts, and salt.
Pound until you have a paste.
Add the chili flesh and pound until fully incorporated (the resulting paste should be slightly coarse).
Heat the frying pan over medium-high heat and add the remaining olive oil.
Add the onion and sauté until lightly golden (3 to 4 minutes).
Add the tomato and salt.
Reduce heat to medium and simmer for 5 minutes.
Add the chili paste, wine, vinegar, red pepper flakes and water or stock of choice. Give a good stir to combine.
Reduce heat to medium low and simmer for to reduce by a quarter (about 15 minutes).
Remove from heat and pass the sauce through a food mill with a medium plate.
Then pass through the food mill again with a fine plate.
The sauce is ready to use hot or cold.