Cut about ¼ inch from the top and bottom of the oranges and grapefruit so they sit flat.
Position the fruit with one of the flat sides down and use a sharp knife to cut in a downward motion, slicing the peel off.
Position the fruit on its side and, with a sharp paring knife, cut the fruit into sections following the natural separations. Cut these sections into smaller pieces
In a small bowl combine the citrus segments with the maple syrup and lime juice, and refrigerate.
Preheat the oven to 425 F.
Combine the flour, sugar, baking powder, baking soda, and salt in a large bowl.
In a medium bowl combine the egg, buttermilk, and vanilla.
Cube the butter.
Add the butter to the dry mixture and mix with your hands or a pastry blender until a crumb mixture forms.
Add the wet ingredients into the bowl and mix until a shaggy dough forms.
Dust flour on a clean work surface and lightly finish mixing the dough until it holds together. With your hands, form it into a 1-inch-thick layer of dough.
Using a 3-inch biscuit cutter, cut out 8 circles of dough and place on the baking sheet.
Bake for 15 minutes, then cool for 15 minutes.
To assemble, split the cooled shortcakes in half.
Add a scoop of whipped cream and a small amount of the citrus fruit.
Top with the other shortcake piece, and add a little more whipped cream, more fruit, zest, and optional fresh mint to garnish. Serve.