Preheat oven at 350F.
In a medium sized bowl, stir together the melted butter or margarine and brown sugar with a rubber spatula.
Stir in eggs and vanilla until smooth.
In a separate small bowl, mix flour, baking powder, salt, matcha powder, white chocolate chips, sliced almonds. Ensure you break up any clumps of matcha powder.
Stir dry ingredients into the sugar mixture until just combined.
Spread batter into 8x8 inch greased or parchment laid pan.
Bake 25 to 30 minutes until edges are barely golden and pulls away from sides of the pan.
Cool in the pan or wire rack.
For clean slices, refrigerate until thoroughly cool, slice and allow to warm back up to room temperature to serve.