Combine the berries, sugar, and lemon juice in a blender. Puree for 1 minute. Scrape the sides of the pitcher and puree for an additional minute, until the mixture is completely smooth.
Pour the finished puree into an airtight container and refrigerate until ready to use.
Notes
After the puree is smooth, you can serve it as is, or pour it into a saucepan and simmer until reduced by about half for a thicker puree. Personally, I like it just the way it is for a light and fresh-tasting strawberry sauce.