This recipe comes from the book Perfect Cakes by Chef Nick Malgieri. I made a few adjustments to the recipe, not much, but don't go broke buying matcha green tea powder when you can make it yourself using ordinary loose leaf green tea. Because I didn't use the bright green-colored matcha tea powder and used unbleached all-purpose flour, the cake itself had a green tea flavor and had a muddy-green color when I took it out of the oven. I also overfilled the loaf pan (the cake does rise by double its volume) and baked the cake for 15 minutes longer that what the original recipe calls for.
You don't need to buy the expensive matcha green tea powder for this recipe. If you have an electric coffee grinder, you can certainly make your own with any type of dried green tea. I used a combination of good quality green tea bags plus some Longjing loose leaf tea. The green tea powder that anyone can make is called konacha, or "powder tea". Since this is for a bread-based dessert, you don't need to get the green tea as finely milled as you can with a coffee grinder, as you might with a mochi or green tea ice cream recipe.
Makes 1 loaf (9" x 5" x 3")
Ingredients
2 c unbleached all-purpose flour
2 tbsp green tea powder
2 tsp baking powder
2 sticks unsalted butter, diced
1 1/2 c powdered sugar
5 large eggs, separated
a pinch of salt
Directions
Preheat oven to 325 degrees F. Butter and line a 9" x 5" x 3" loaf pan with parchment paper.
1. Separate the eggs into yolks and whites. A small bowl for the yolks, and a 5-qt mixing bowl for the whites.
2. In a large bowl, sift together flour, tea powder, baking powder, and powdered sugar. Cut in butter with a pastry blender (or toss in all these ingredients in step 1 into a food processor and pulse until crumbs form). Gently fold in one egg yolk at a time with a rubber spatula.
3. Add the pinch of salt to the egg whites and beat with a balloon whisk (or use an electric mixer with a balloon whisk attachment) until medium peaks form. When you lift the whisk out of the eggs, the foam should mostly hold its shape and be white and opaque in color.
4. Gently fold the egg whites into the flour mixture until no white streaks remain.
5. Fill a prepared loaf pan with the batter half way, the cake will rise and double in volume. Bake for 50 minutes, or until a skewer comes out clean. Let it cool for 10 minutes in the pan on a rack before slicing.