Prepare the egg mixture: Crack the egg into a large mixing bowl and add the granulated sugar and honey. Use a hand mixer to beat the mixture until it becomes pale and thick, about 3-4 minutes. This creates a light and airy texture for the madeleines.
Sift and combine dry ingredients: In a separate bowl, sift together the all-purpose flour, matcha powder, and baking powder. Sift twice for a smoother batter. Gently fold the dry ingredients into the egg mixture using a whisk. Stir just until the batter is smooth and no lumps remain.
Incorporate the butter: Melt the butter in a microwave-safe container (around 1 minute at 500W). Once melted, let it cool slightly before slowly pouring it into the batter. Mix gently until the butter is fully incorporated and the batter becomes smooth.
Prepare the mold: Melt a small amount of extra butter and use a brush to coat the madeleine mold. Place the mold in the refrigerator to chill until the butter solidifies. Once set, dust the mold with flour, then tap out the excess to prevent sticking.
Rest the batter: Spoon the batter into the prepared mold, filling each cavity about 3/4 full. Tap the mold lightly on the table to release any air bubbles. Let the filled mold rest in the refrigerator for 15-20 minutes. This helps the madeleines rise evenly during baking.
Bake the madeleines: Preheat the oven to 180°C (350°F). Remove the mold from the refrigerator and bake for 10-12 minutes, or until the madeleines turn golden around the edges and spring back when gently pressed in the center.
Cool and store: Remove the madeleines from the oven and carefully transfer them to a cooling rack. Cover them with aluminum foil to retain moisture as they cool. Once fully cooled, store the madeleines in an airtight container or a sealed bag.
