Preheat the oven to 190ºC (375ºF), and line 2 large baking pan and line with baking paper.
In a large mixing bowl, whisk together the flour, salt, baking powder and, baking soda.
In another large mixing bowl, using a hand mixer, beat the butter, sugar, and lemon zest together until light and fluffy.
Add the eggs, one at a time, beating after every egg.
Add the vanilla and almond extract.
Add all the dry ingredients to the butter mixture and beat until just combined.
Add the sour cream and milk beat until just combined.
Using a large cookie scoop, (about ¼ cup) scoop dough onto your prepared baking paper, 5 cm (3 inches) apart.
Bake until the edges are golden brown and tops are just set, 12 to15 minutes.
Place the cookies on an oven cooling wire rack let it cool completely.
In the meantime, you can start with the frosting. In a large mixing bowl, combine the icing sugar, corn syrup, 5 tablespoons hot water, and vanilla essence. Add more hot water, 1 teaspoon at a time until a spreadable consistency is reached.
A thicker icing is better than a thin icing for these cookies.
Place about half of the icing into another bowl.
Add cocoa powder and 1 tablespoon hot water and mix until well combined.
Add more hot water 1 teaspoon at a time until a spreadable consistency is reached.
Flip the cookies around using the flat side to spread the vanilla icing on one side of each cookie, let it set until hardened about 15 minutes.
Spread the chocolate icing on the other half of each cookie and let it set until hardened about 15 minutes before serving.