A good full bodied Majani black tea will impart a wonderful subtle nuttiness with just a hint of malt to the shortbread.
1 lb unsalted butter
1 cup sugar
4 cups AP flour
2 teaspoons bourbon
4 teaspoons finely ground Kenyan black tea
Cream together cold butter and sugar. Grind tea in spice grinder until fine but not powdered. You want some texture left to it. Add flour, salt, tea and bourbon. Mix until just pulls together. Roll out to 1/4” thick and chill. Cut and bake on parchment or oiled sheetpan at 250 degrees for around 45 minutes.
For a fun change of pace try adding finely chopped chocolate or a pinch of ground clove or cardamom.
Reduce the sugar by half for a more savory shortbread. This works very nicely paired for instance with a wedge of blue cheese, some lightly dressed greens and roasted figs.