Mix the milk with the apple cider vinegar and set aside to create your soy buttermilk.
In a large bowl, use a mixer to cream together the butter and sugar.
Stir in the soy buttermilk and mix until smooth.
Add the almond butter and mix until smooth.
In a separate small bowl, combine the flour, ground flax seed, baking powder and salt. Stir until combined.
Add the dry ingredients to the wet and mix well.
Form the dough into a ball and wrap in plastic wrap. Refrigerate for at least one hour.
When you're ready to bake the cookies, begin by heating your oven to 350F.
On a lightly floured surface, roll out the dough to 1/4 inch thickness. Cut into desired shapes with cookie cutters. There's not a lot of spread to these cookies so you can place them fairly close together on the cookie sheet, just not touching.
Bake for 10 - 12 minutes, until bottoms and edges just start to lightly brown. Remove from baking sheet and cool on wire racks.
After the cookies have cooled, place a dab of Chocolate Filling on the bottom half of one cookie and sandwich it with the bottom half of another cookie.
Store in an airtight container