1.Brush four 4 ounce ramekins with butter, using upward strokes. Put 1 teaspoon sugar in each ramekins and rotate the ramekin to dust the insides with sugar. Remove excess sugar from the ramekin and chill in refrigerator to set.
2.In a large bowl, beat the egg yolks and 2 tablespoons sugar together. Sift flour into egg mixture and mix well. Set aside.
3.In a small pot heat the milk and heavy cream until almost boiling.
4.Add a splash of hot milk into the egg mixture and whisk well until the mixture is smooth. Then gradually whisk in the rest of the milk mixture. Pour the mixture back into the saucepan. Whisk the mixture over a medium-low heat for 3-4 minutes until thickened and smooth.
5.When the custard has thickened, immediately transfer to a bowl. Cover with plastic wrap and cool to room temperature for about 30 minutes.
6.Preheat the oven to 390 degrees. Add egg whites to the bowl of a standing mixer fitted with a whisk attachment and set to level 3 for 2 minutes. Start adding 1/4 cup sugar gradually a spoonful at a time. Once you add all the sugar, increase the speed to Level 8 and whisk to make a firm, glossy meringue, about 3-4 minutes.
7.Unwrap the custard and sift matcha green tea powder into the custard. Mix well.
8.Whisk 1/3 of the meringue into the custard and mix until homogenous. Very carefully fold in the rest of the meringue using a rubber spatula. Do not over mix.
9.Divide the souffle mix into 4 ramekins. Tap them on the work surface to level the mixture and run your thumb around the edge. Place the ramekins on a baking sheet and bake for 12-15 minutes until well risen and slightly golden on top. The souffle should wobble gently in the middle when it’s ready. Dust with powder sugar and place on a plate. Serve immediately.