Here's a sampling of what I feed my Testudo graeca hatchlings. I believe that variety is key, and it gives them something different to enjoy each day.
They get plain, moistened Mazuri.
Spineless prickly pear cactus. I dice it up so it's easier for them to eat. Sometimes I also mix it with Mazuri.
Spineless prickly pear cactus blended with optunia fruit, and a hibiscus flower on the side.
Natural weeds, leaves, and flowers, grown from seed.
Organic "store bought" greens. I mix a batch consisting of escarole, endive, red leaf lettuce, green leaf lettuce, romaine lettuce, dandelion greens, and a little radicchio.
Optinia fruit chunks, with a hibiscus flower.