Beat the butter and sugar until fluffy and creamy. Add the milk and puréed tofu and mix. Add the vanilla, brandy, and lemon zest; mix well and set aside.

In a separate bowl, whisk together the flour, cornstarch, salt, baking soda, and baking powder. Add the dry mixture to the butter mixture and work together with your hands until combined and soft. Do not add any extra flour. Cover and chill in the refrigerator for 2 hours.

Preheat the oven to 325°F (170°C, or gas mark 3). Line baking sheets with parchment paper. Divide the dough in half and keep half refrigerated. On a floured work surface and using a floured rolling pin, roll out the dough to a thickness of 1/4 inch (6 mm). Cut into 2-inch (5 cm) rounds with a cookie cutter and transfer to the prepared baking sheets. Repeat with the remaining half of the cookie dough.

Bake for 12 to 15 minutes, or until golden. The cookies should be dry but not brown.

Mix all the ingredients in a pot and cook over medium heat until it the caramel starts to pull away from the sides of the pot. You may want to prepare this in a double boiler so you lessen the chance of scorching the mixture. Remove from the heat and let cool and thicken before filling the cookie sandwiches.

When the cookies are cool, match them up into pairs of like sizes.

Turn one cookie over and spread a dollop of dulce de leche onto the flat part of the cookie (it is much easier to spread when the dulce is warm). Place its partner on top (flat side down) and gently press so that the caramel comes to the edges. Roll the edges in the coconut and place on a rack to set. Repeat with the remaining cookie pairs.

When ready to serve, sift a light layer of confectioners’ sugar over the tops of the cookies and place them on a platter.