The first time I tasted ajo blanco, Spain’s white gazpacho, I was surprised. Surprised that as a fan of the better-known tomato gazpacho and a lover of Spanish food generally, I had somehow missed this elegant little number. Surprised that it was so creamy without any dairy products. And surprised at how simple it was to make — and how impressive to serve. That was almost 15 years ago, when Boston chef Gabriel Frasca showed me his version of the classic, blended from almonds, bread, olive oil, sherry vinegar and garlic — and garnished with more almonds and purple chive blossoms.