First, melt the butter completely and allow to cool. Use a little of the melted butter to grease your madeleine tray.
In a large bowl, whisk together the eggs, sugar and vanilla essence for a few minutes until frothy. Add most of the melted butter and mix gently.
In a second bowl, mix the flour, baking powder and green tea powder. Sieve the flour mix into the egg and sugar mix, whisking all the ingredients together gently until well combined. Let this batter rest for 20 minutes.
Heat your oven to 200c/180c fan/Gas Mark 6. Once the batter has rested for 20 minutes, carefully spoon it into your greased madeleine tray. Cook for 8 to 10 minutes or until the mixture has risen a little in the middle and is cooked through. Transfer the little green tea cakes to a wire rack and allow to cool.
Madeleines are best eaten on the day they’re baked and are particularly good dunked in coffee or tea.