Put Toasted Black Sesame Seeds (1/2 cup), in a food processor and process until almost all the seeds have been ground into a powder.
Add Honey (1/2 cup), to the black sesame powder and continue to process until mixture turns into a thick paste.
Preheat oven to 350 degrees F (180 degrees C) and prepare your mini bundt cake pan by brushing the wells with Butter (1 tablespoon) then dusting them with Dark Cocoa Powder (1 teaspoon).
In a bowl, whisk together the All-Purpose Flour (150 gram), Black Cocoa Powder (3 tablespoon), Baking Powder (1 teaspoon) and Salt (1/2 teaspoon).
In the bowl of a stand mixer (or a large bowl with an electric mixer), blend Buttermilk (2 cup),Unsalted Butter (1 cup), Granulated Sugar (1/2 cup), Vanilla Extract (2 teaspoon), and prepared black sesame paste on medium speed until pale and creamy. Reduce speed to low and add Egg (2), one at a time, mixing well after each egg. Add in the vanilla extract & mix until incorporated.
Alternately add the flour mixture & buttermilk in three additions, mix until just combined.
Spoon batter evenly into the wells of the prepared bundt cake pan and bake for 20 minutes
Let cakes cool in pan for 5 minutes, then invert onto a rack to cool completely
For the glaze place the finely chopped White Chocolate (4 ounce) in a heat safe bowl.
Sift the Matcha Powder (1 teaspoon) into a saucepan, add 2 tablespoons of the Heavy Cream (1/4 cup) and whisk until perfectly smooth.
Whisk in the remaining heavy cream and heat mixture over medium heat, stirring often, until it just begins to boil
Remove mixture from the heat and then pour it over the chopped white chocolate.
Allow the hot matcha cream to melt the chocolate a bit and then stir until the white chocolate is fully melted - the glaze should be a thick pourable consistency.
Place the rack with the black sesame bundt cakes over a piece of parchment paper and pour glaze over the cooled cakes
Allow glaze to set before serving. Enjoy!