I used a recipe for strawberry gelato, but substituted a mix of blueberry, raspberry and strawberry.
The mix makes a pretty good popsicle too.
Should have some blackberries for dyeing soon. This is red cabbage (the velvet), marigold (the cream-ish strip, it's a bit more yellow in person), and yellow over-dyed with a commercial blue dye. It was time to make a little bag for my bus knitting.