Preheat the oven to 350 degrees F (175 degrees C). Oil a loaf pan.
Combine raisins and tea in a bowl. Steep for about 30 minutes.
Mix flour, sugar, and allspice together in a second bowl. Add the raisin-tea mixture and egg. Gently combine using a rubber spatula; do not overmix. Scoop mixture into the prepared loaf pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 1 hour.