With a citrus zester, zest two mandarin oranges and then peel the skin off the oranges and divide into sections. Next, slice all the orange sections into small pieces. Reserve any juice to add to the batter.
In a large bowl mix the flour, sugar, baking powder, baking soda and salt.
Cut the cold butter into small cubes and then add to the flour mixture. Cut in butter with two knives or a pastry cutter until the mixture is the size of peas. Next add the buttermilk, orange zest, and mandarin oranges pieces.
Gently stir this mixture with a wooden spoon until all the flour is incorporated.
Turn dough onto a well-floured board and knead the dough until it comes together; add flour as needed if the dough is sticky.
Press the dough into and a round disk about 1/4" thick then cut into eight wedges Transfer the wedges to a parchment lined baking sheet and bake for 15 to 17 minutes.