Preheat the oven to 375 degrees F. In a food processor, fitted with a metal blade, combine the almonds and brown sugar. Process until completely ground. Using an electric mixer, fitted with a whip attachment, whip the egg whites and cream of tartar on low speed until frothy. Add 1 1/2 cups of confectioners sugar. Increase the speed to medium-high and continue whipping until very stiff peaks and the whites just begin to slip and streak around the side of the bowl. Remove the bowl from the mixture and fold in the almond and sugar mixture. When almost completely incorporated, add the 2 teaspoons of coffee and continue folding until mixed. The batter must be smooth an shiny, and it should spread easily without being runny. If it is dull and firm, fold it a little longer to deflate it slightly and get the required consistency. But do not deflate it too much or the batter with spread too much and the tops of the cookies will crack when baked. Fill a large pastry bag, fitted with a 3/4 inch plain pastry tube, with the batter. Line two half sheet pans with parchment paper. Pipe the domes in staggering rows 1 inch wide and 1 inch apart. Unless you have 2 ovens, pipe only 1 sheet of cookies at a time. Bake for 1 minute. Place an empty baking sheet underneath the sheet of cookies, and continue baking, using a wooden spatula to hold the oven door ajar, until the tops of the cookies are very lightly browned and dry to the touch white the insides are still soft and the bottoms still pale, about 8 to 10 minutes. Lift the baking sheet of cookies off the empty baking sheet and take it to the sink. Pour cold water, about 1/2 cup, between the paper and the baking sheet (tilting the baking sheet so that the water runs over the entire surface and drains thoroughly into the sink) to steam the cookies off the paper. Then place the baking sheet on a wire rack and cool. Spread the bottoms of half the cookies with some of the Ganache. Place the remaining cookies, right side up, on top of the Ganache, pressing slightly to form a sandwich. Place the filled macaroons on a serving plate.
Chop the chocolate and put it in a small stainless steel bowl. Bring the cream just to a boil, then reduce the heat and simmer for 2 minutes, stirring constantly with a wire whisk. Gradually stir the cream into the chocolate with the whisk and continue stirring until the chocolate is completely melted. Then, allow it to cool, stirring occasionally with a wooden spatula, until it starts to thicken.
Recipe adapted from The French Cookie Book, by Bruce Healy with Paul Bugat, published by William Morrow, 1994