Place dried chile in a heatproof bowl and pour in boiling water to cover. Let soak for 30 minutes until softened. Drain, remove stem, then slit the chile and scrape out the seeds with a small sharp knife. Chop the flesh roughly and set it aside.
Heat the oil in a frying pan and saute the onion and garlic until soft.
Cut a cross in the bottom of each tomato. Place them in a heatproof bowl and pour in boiling water to cover. After 3 minutes, life the tomatoes out on a slotted spoon and plunge them into a bowl of cold water. Drain,. The skins will have begun to peel off.
Skin the tomatoes completely, then cut them in half and scoop out the seeds. Chop the flesh into 1/2 inch cubes and add it to the onion mixture with the chopped chile. Stir in the ground cumin and cook 10 minutes.
Put the mixture in a food processor or blender. Add the stock and process on high speed until smooth.
Pour the mixture into a large saucepan, add the ground almonds and stir over low heat for 2-3 minutes. Stir in the creme fraiche until it has been incorporated completely.
Squeeze the lime juice and stir it into the sauce. Season with salt to taste.Increase heat and bring it to a simmering point.
Add the shrimp and heat for 2-3 minutes, depending on the size. SERve on a bed of rice and pass warm tortillas separately.