How young do you mean by "baby?" Most people would advise you not to give this animal anything other than hay, water, and pellets until it is about 3 months old, then introduce new one at a time and in small amounts.
Personally, I treat my bunnies to greens when they become interested like cilantro, dandelion leaves, violets - flower and leaves, strawberry leaves, carrot greens, and perhaps spring green mixes, although my rabbits chose salad greens last typically.
Rabbits may like carrots, fruits, and even tomatoes but these are not a favorites of mine to give a rabbit: too high in sugar. They can cause problems with their digestive tract.