Puree in a blender or food processor:

Use a silicone spatula to push the pulp through a fine-mesh sieve into a bowl. Press firmly, and periodically scrape the inside of the sieve clear of seeds, which will otherwise plug up the holes. Do not waste any of the precious pulp. Continue to press until you are left with just a heaping tablespoon of stiff, clumped-together seeds. Taste the pulp, then stir in a little more sugar or lemon juice, if needed. Serve, at room temperature or chilled. Cover and refrigerate for up to 3 days.