Put the butter, sugar and chocolate in that order into a 2 quart saucepan. Put the pan over low heat and warm the ingredients, stirring occasionally, until they are melted and smooth. Scrape everything into the bowl of a mixer or into a large bowl.
Sift together the flour, cocoa, baking soda, salt, cinnamon and cloves.
Working with a mixer with a paddle attachment, if you have one, or with a hand mixer in a large bowl on low speed, add the eggs, one at a time, beating until the eggs are well blended into the chocolate. With the mixer still on low, add the dry ingredients, mixing just until the dough is smooth and shiny; it will clean the sides of the bowl and form a ball. Turn the dough out onto a work surface, divide it in half, wrap each piece in plastic wrap and chill for at least 1 hour or for up to 3 days. (If the dough is solid, leave it on the counter for 30 minutes before proceeding.).
Position the racks to divide the oven into thirds and preheat the oven to 350°F Line two baking sheets with parchment or a silicone mat.
Working with 1 tablespoon of dough at a time, roll the dough between your palms to form firm, shiny balls. (If the dough breaks as you work, squeeze and knead it a bit, then reroll it between your palms.) Place the balls about 1 inch apart on the baking sheets and lightly press each one down a bit with your fingertips.
Bake the cookies for 10 to 12 minutes, rotating the baking sheets from top to bottom and front to back at the midway point. The cookies should be delicately firm and crackled across the top. (It’s better to under- than over bake.) Remove the sheets from the oven, let the cookies rest on the sheets for 2 minutes, then, using a wide metal spatula, gently transfer the cookies to a rack; cool to room temperature.
Repeat with the remaining dough, cooling the baking sheets between batches.