Preheat oven to 350°F. Prepare an 8"x 8" pan by greasing and dusting with flour or lining with parchment paper. Place the diced prunes and the tea in a small bowl. Heat the water to boiling in the microwave. Pour the water over the plums and set aside to moisten.

Mix the flour, baking powder, salt, and nutmeg together in another bowl. Set aside. Cream the butter and sugar together. Add the eggs and beat until light and fluffy. Add the plums and tea (do not drain) and the nuts and combine. Add the dry ingredients and combine. Add enough milk (about 2 tbsp.) to make a soft batter.

Remove the batter to the prepared pan. Bake for 35-40 min. or until the pudding is set in the middle (test with a toothpick). Cool in the pan on a wire rack for 5 min., then invert to remove the pan. Continue cooling on a wire rack.

For the plum sauce: Melt the butter in a saucepan. Stir in the sugar, cornstarch, brewed tea, and condensed milk. Heat until boiling and bubbling. Remove from the heat and add rum or vanilla. Serve the plum pudding topped with sauce.