Preheat oven to 400 degrees F.
Mix together dry ingredients in a large bowl; flour, baking powder, salt, brown sugar, and cinnamon. Using a pastry blender, cut in the butter to coat pieces with flour. The mixture should look like coarse crumbs. Make a well in the center of the bowl and pour in the heavy cream and vanilla extract. Fold everything together just to incorporate as much of the flour as possible; do not overwork. When you have shreds of dough, pour the dough out onto a floured surface and finishing working the dough into a ball there.
Pat the dough out into a rectangle. Using a bench knife, cut the dough rectangle in half, then each half in half. Cut down the middle to form 8 squares and then cut each square on the diagonal to form 16 triangles.
Transfer each triangle to a baking sheet covered in parchment paper, leaving an inch or two of space between each wedge. Bake for 12-17 minutes until golden brown. Allow to cool on the baking sheet for 2 minutes before transferring to a cooling rack. Cool completely before drizzling with glaze.