When I was searching for Andalusian soup recipes, I found this authentic recipe from that region. It sounds very, very rich and wonderful, and you could use it as a sauce instead of a soup.
1/2 lb crusty white bread, crusts removed
4 oz raw peeled almonds*
2 cloves garlic
7 cups water
1 cup olive oil
Red wine vinegar, to taste
Possible garnishes: Seedless grapes, apple slices, melon, shrimp, or sliced roasted almonds.
Soak the bread in water. In a powerful blender or food processor, grind the almonds with the garlic and a little salt, as fine as you can (the finer they are ground, the creamier the result will be). Then add the soaked bread and blend until you get a white homogeneous paste. Still blending, slowly add the oil in a thread, as you would in a mayonnaise. Then combine the vinegar and water and very slowly add them in a thin stream while blending.
Serve very cold with the garnish of your choice.
*I’ve never tried to peel an almond. But evidently, you can dip them in boiling water for a few seconds, and then the dark skins will pop off.