Line a baking sheet with parchment paper or a nonstick baking mat.
Slice bananas into 1-inch coins and spread evenly onto the baking mat, forming a tight rectangle.
Spread your nut butter of choice all over the banana pieces.
Melt down vegan white chocolate in 30 second increments in the microwave, stirring in between, until fully melted. Sift in matcha powder and stir to combine.
Drizzle the chocolate over the nut butter, using a spatula to smooth and evenly spread. Sprinkle with salt if using.
Transfer the baking sheet to the freezer and let chill for 1 hour or until firm to the touch. To enjoy, break up the bark with your hands to create bite sized pieces.