Feeling whimsical, and in the mood for a cool cocktail one very hot afternoon, I began dreaming of a Dark & Stormy, a cocktail usually made with dark rum, lime and ginger beer. Why isn’t it ever served frozen, I wondered? The experiments began, one involving a Key Lime sorbet I discovered at the snappy new Guilford Food Center on the Guilford Green. Instead I asked them to cut up one of their fresh pineapples for me. I went home and froze the chunks.