In a large bowl whisk dry ingredients: flour), baking powder, baking soda, salt, cinnamon.
In a separate bowl whisk together wet ingredients: butter, milk, yogurt, eggs, vanilla, and sugar.
Combine wet with dry ingredients until just incorporated and add fruit or nuts at this point, folding into mix.
Grease muffin pans or add muffin papers and fill to ½ inch below top .
Bake for 18-20 minutes, testing with a toothpick at 15 minutes to see if comes out clean. Ovens vary so be cautious not to over bake.
Let cool in pan for 5 minutes before removing to a rack to cool completely.
Notes
Eat within 2 days unrefrigerated. They can be kept up to 4 days in the fridge or frozen for 2 months.
You may use any combination of flours here. All buckwheat or all whole wheat or any mix. I use soft white wheat if grinding my own.
Keep in mind that buckwheat IS gluten free so these are only GF if you use all buckwheat. You can also use a 1-to-1 GF baking blend in place of whole wheat flour.