In the bowl of a stand-mixer with the paddle attachment, or in a large bowl with a hand mixer, cream the butter and sugar until combined and creamy, about 4 minutes.

Add the eggs to the bowl and mix until evenly combined

Stir in the flour, baking soda, and cream of tartar until fully incorporated and no clumps of flour are visible. 

Stir in the milk, vanilla extract, and orange zest, using your hands to bring the dough together in the end.  Wrap the dough into two large disks, wrap in cling film, and refrigerate for 30 minutes to allow the butter to firm up slightly.

While your dough chills, preheat your oven to 350° F and line two baking trays with  parchment paper or a silpat liner.

Sprinkle flour over a work surface and place one disk of dough in the center.  Dust flour over a rolling pin and roll the cookie dough to about ¼-½ inch thick.  Usea round cookie cutter to cut out circles of the dough and place on the baking tray.  Re-roll the dough and repeat the same process until all of the dough is used (don’t worry, this dough is very hard to overwork).

Bake the cookies for 10-12 minutes, until just golden around the bottom.  Let the cookies cool on the tray for 5 minutes then transfer to a wire rack to cool completely.

While the cookies cool, melt ⅔ of the chocolate chips in a microwave. Run the microwave for 30 second increments and stir between each until melted and very smooth.

Add the remaining chocolate chips to the melted ones and stir to incorporate in, letting them slowly melt in. This is a simple way to temper the chocolate and will give your chocolate a nice texture once they’re dipped.

Dip one half of the cooled orange sugar cookies into the chocolate and set onto a piece of parchment or wax paper. Once the chocolate has set slightly, about 2-3 minutes, sprinkle each cookie with some flaky sea salt to taste.

Let the chocolate set completely and enjoy! Store leftovers in an airtight container at room temperature for up to 4 days. Enjoy!