Step 1: In a large bowl, whisk together the flour, granulated sugar, and salt. In a separate medium bowl, whisk the eggs, milk, melted butter, vanilla extract, and 2 tablespoons of matcha powder until well combined.
Step 2: Gradually pour the wet ingredients into the dry ingredients, whisking continuously until a smooth batter forms. For extra smooth crêpes, strain the batter through a fine-mesh sieve into another bowl. Cover and refrigerate for at least 30 minutes, or up to 2 hours, to allow the gluten to relax.
Step 3: Heat a 8-inch non-stick crêpe pan or skillet over medium-low heat. Lightly grease the pan with a tiny bit of butter or oil. Pour about 1/4 cup of batter into the center, immediately tilting and swirling the pan to spread the batter thinly and evenly across the bottom. Cook for 1-2 minutes until the edges are golden and the crêpe releases easily. Flip with a thin spatula and cook for another 30-60 seconds. Slide the cooked crêpe onto a plate.
Step 4: Repeat with the remaining batter, stacking the crêpes as you go. You should get about 20-25 crêpes. Allow them to cool completely before assembling the cake.
Step 5: In a large, chilled bowl, combine the cold heavy cream, powdered sugar, and 1-2 tablespoons of matcha powder (adjust to your preferred matcha strength). Using an electric mixer, beat on medium-high speed until stiff peaks form. Be careful not to overmix.
Step 6: To assemble, place one cooled crêpe on your serving plate or cake stand. Spread a thin, even layer of matcha whipped cream over the entire surface using an offset spatula. Place another crêpe on top and repeat the layering process with crêpes and cream until all crêpes are used.
Step 7: Smooth the sides and top of the cake with any remaining cream. Cover the Matcha Mille Crêpe Cake loosely with plastic wrap and refrigerate for at least 4 hours, or ideally overnight. This chilling time is crucial for the cake to set and for the flavors to meld.
Step 8: Before serving, dust the top generously with extra matcha powder using a fine-mesh sieve. Slice with a sharp, thin knife and enjoy your elegant Matcha Mille Crêpe Cake!