Preheat the oven to 375 degrees. Line the muffin pan.
In a large bowl, combine the dry ingredients: the flours, sugar, salt, baking powder and baking soda.
In a separate bowl, mash up the banana and add the wet ingredients: greek yogurt and milk. Give it a stir then add it to the dry ingredients along with the eggs. Whisk to combine.
In another bowl for the streusel, combine the sugar, brown sugar, gluten free flour, spices and the cold butter. Cut in with a pastry blender or use your fingertips to combine. Continue to combine until it resemble coarse meal. Set it aside.
Gently fold in the blueberries to the batter.
Divide 1/2 of the batter between the tins. Then add scoop a little of the streusel into the muffin. Fill with remaining batter and then add the other half of the streusel on top.
Bake for 20 minutes.
Remove from the oven and let it cool for 10 minutes. Serve warm and enjoy!
Notes
The buckwheat measurement is correct- use 1/3 cup plus an additional 1/2 cup.Honey, butter, pumpkin spread and powdered sugar are all good toppings for these yummy muffins. They freeze well and can be reheated for 30-45 seconds in the microwave.Fresh or frozen blueberries can be used. If you are using frozen, put them in a strainer and let them thaw before using.