Preheat oven to 160 °Celsius.
Pour milk into a small pot and heat up until the sides start to bubble. Turn off the heat and dip 3 Earl Grey tea bags into the milk. Cover the pot and let the tea steep in the hot milk for 3 minutes.
Remove the tea bags (squeeze out all the tea with the back of a spoon) and discard them. Leave the tea-infused milk aside to cool.
Cut the remaining one tea bag and pour the tea leaves into a food processor. Add approximately 3 to 4 tablespoons of the granulated sugar and blend both until the tea comes to a fine powder. Transfer the sugar-tea leaves mixture into a large mixing bowl.
Add the remaining granulated sugar to the bowl, followed by the butter.
Cream the butter, sugar and the ground tea leaves until light and fluffy. Scrape the sides of the bowl half way through.
Add the eggs into the creamed mixture, one at a time. Each time, beat until all the traces of the egg is no longer visible. Scrape the sides and bottom of the bowl.
Sift in the flour, salt and baking powder into the creamed ingredients and fold these dry ingredients into the creamed mixture alternately with the tea infused milk in 3 batches. Start and end with the flour mixture.
Divide the cake batter into 2 well greased and floured 7 inches round cake tins.
Level the tops and bake at 160°Celsius for 45 minutes.
Test the cakes at 40 minutes by inserting a skewer in the center of the cakes. If the skewer comes out without any wet batter sticking to it, the cakes are done and can be removed from the oven. Otherwise, let them bake further until the 45 minutes is up.
Remove cakes from the oven and let them cool in the tins for about 2 to 3 minutes before turning them out onto wire racks to cool completely before decorating.