In a medium bowl, whisk together the flour, baking powder, baking soda and salt.  Set aside.

In a stand mixer fitted with a paddle attachment, cream the butter and sugar on medium speed for 2-3 minutes, until the mixture is light and fluffy. 

Add one egg at a time, making sure to mix thoroughly before adding the next.  Pour in the buttermilk and the extracts followed by the lemon zest.  The mixture will look a little curdled.  Trust the process, keep going. 

Turn the mixer on low  and add a half cup of flour at a time and mix until smooth.  The dough will be very soft.  Place plastic wrap directly on top of the dough and refrigerate the dough in the bowl for one hour.  After the dough has solidified, divide the dough into two pieces and wrap in the plastic wrap.  Refrigerate for at least a couple more hours or overnight. 

Preheat the oven to 375ºF. 

Sprinkle a work surface with a generous layer of flour.  Roll the dough out to about ¼ inch thickness.  Flour a 1 ½ inch biscuit cutter and cut out the tea cakes.   Gather the scraps and reroll and cut more tea cakes until you run out of dough.  

Place the cookies on a parchment lined cookie sheet and sprinkle the cookies with the Demerara Sugar. 

Bake for 8-10 minutes.  After removing the cookies from the oven, cool on the pan for 2 minutes before removing them to a wire rack. 

The tea cakes will keep for 2 weeks in an airtight container.