In a small spice grinder, blitz the tea leaves until finely ground. If you use tea bags, you can use them directly. Just cut the bags and add.
In a large bowl, add eggs and castor sugar. Using a whisk, mix them lightly for 3-4 minutes or until the sugar is dissolved.
Sift in cake flour, earl grey tea powder, and baking powder. Whisk until well combined.
Add melted butter and whisk until well incorporated.
Cover the bowl with plastic wrap and chill the batter for at least 1 hour or overnight.
When you are ready to bake, preheat the oven to 400℉/200℃. Grease a non-stick madeleine pan with butter. If you are not using a non-stick pan, grease the pan with butter and dust the wells with flour lightly.
Remove the batter from the fridge. Using a spatula, mix to loosen the batter and remove the air bubbles.
Transfer the batter into a piping bag and pipe the batter into the molds until 80-90% full. You can also alternatively spoon the batter into the molds.
Place the filled madeleine pan into the preheated oven and immediately reduce the oven temperature to 350℉/180℃. Bake for 10-12 minutes or until they have risen and golden brown.
Remove madeleines from the pan immediately. Cool completely.
Glaze
Steep earl grey tea leaves in hot water for 5 minutes. Strain out the tea.
In a medium bowl, sift the confectioners' sugar. Add earl grey tea. Mix until a thick brown paste forms. You can adjust the consistency by adding more tea/water to make the glaze thinner or confectioners' sugar to make it thicker.
Brush the shell side of the madeleines with the glaze. Place the madeleines with the shell side up to set the glaze.
Notes
Making the recipe using weight measurement is recommended for the best result.Letting the batter rest in the refrigerator ultimately helps the humps rise up taller in the oven.