Preparation:
In a heavy Dutch oven or stockpot, melt butter over moderate heat and sauté the onions, half of the piquillos, salt and pepper until the onions turn a light golden color, 5 to 7 minutes. Stir in the garlic and cook briefly just to release the aroma, 1 to 2 minutes.

Pour in the stock, add the potatoes and bring to a boil. Reduce to simmer and cook until the potatoes are tender, about 20 minutes. Puree in a food processor or blender just until smooth, being careful not to over-process. Overworking will result in a gummy soup. Return to the pot, stir in the crème fraiche or sour cream and bring just to a boil. Julienne half of the remaining piquillos. Reserve 1 tablespoon julienned piquillos for garnish, and stir the remaining julienned piquillos into the soup.

Puree the remaining whole piquillos in a mini-processor and put in a bowl. Whip the cream until soft peaks form and genlty fold in the pureed piquillos and grated Manchego.

Divide hot soup into bowls, top each with a dollop of the piquillo cream and reserved julienned piquillos and serve.