Preheat the oven to 410°F/210°C and line a muffin pan with paper liners.
In a bowl, sift the gluten-free baking flour, kinako, baking powder, baking soda, salt, and set aside.
In a large bowl, cream together the unsalted butter and sugar. Add the eggs one at a time, and then the greek yogurt and vanilla extract. Stir until combined.
Add the dry ingredients into the wet ingredients and stir until combined.
Fill each muffin well about halfway up, add a couple teaspoons of the kinako butter, and top with more muffin batter. Sprinkle each muffin with the streusel.
Bake at 410°F/210°C for 5 minutes, then turn down the temperature to 374°F/190°C and bake for an additional 15 minutes.
Cool in the pan for 5 minutes before taking them out onto a wire rack to cool completely.