1. Make the cookies: Preheat oven to 325 degrees. Sift together flour, cocoa powder, baking soda, and 1/2 teaspoon salt in a medium bowl. Heat butter and semisweet chocolate in a heatproof bowl set over a pan of simmering water until melted.

2. Beat sugar, eggs, vanilla, and melted-chocolate mixture with a mixer on medium speed until combined. Reduce speed to low, and gradually beat in flour mixture until just combined. Divide dough in half, and fold milk-chocolate chunks into 1 half.

3. Using a 1 1/2-inch ice cream scoop, drop dough onto parchment-lined baking sheets, spacing about 2 inches apart. Bake, rotating and tapping sheets on counter halfway through, until cookies are flat and surfaces begin to crack, 15 to 17 minutes. Transfer cookies on parchment to a wire rack, and let cool.

4. Meanwhile, make the candied almonds: Raise oven temperature to 350 degrees. Coat a baking sheet with cooking spray. Bring sugar, butter, corn syrup, and 1/4 teaspoon salt to a boil in a small saucepan. Add almonds, and stir to coat. Spread out onto baking sheet, and bake, tossing occasionally to recoat nuts, until golden, about 10 minutes. Let cool. Finely chop nuts, and sift to discard dust.

5. Assemble the sandwiches: Using a 2 1/2-inch ice cream scoop, drop ice cream onto half of the cookies. Top with remaining cookies (group plain chocolate cookies together and milk-chocolate-chunk cookies together). Press down gently to push ice cream to edge of cookies. Place candied almonds and coconut in 2 separate bowls. Roll outside of each milk-chocolate-chunk sandwich in almonds; transfer to a baking sheet. Roll outside of each chocolate sandwich in coconut; transfer to baking sheet. Freeze until ready to serve.