I don't drink tea that often during the summer since it's hot, and so the tea leaves I have around tend to lose their flavor. To save the tea, I make hoji-cha! You only need a frying pan, it is so easy.
Sift the leaves to remove any small leaves and fine particles (fine particles will burn very easily).
As much as possible, use a frying pan with a thick bottom that conducts heat evenly.
When the pan is hot, add in the tea leaves. Shake the pan continuously over high heat. Move the leaves around to keep them from burning. When the leaves turn brown, you are done.
The leaves will burn from the residual heat, so remove them from the pan quickly and put them in a clean bottle or container to store.
Hoji-cha has very little caffeine, so it is recommended for children or pregnant women.
Story Behind this Recipe
My mother would always give old tea leaves a second life by roasting them.
The tea will become bitter if you burn the leaves, so you want to stop just before you think they're just right. Once you become used to making this, you can try figuring out how roasted you want your tea leaves to be. Heat it evenly without putting too many leaves in the pan. Apparently the roasting decreases the caffeine content in the tea.