A camera-ready macaron has a smooth top and the coveted "foot": a lacy ring around the bottom. But macarons are tres temperamental. These detailed directions - and practice - will guide you to macaron success. If your first batch is less than perfect, savor your macarons in all their crispy chewy glory, and try again.
Position an oven rack in the center of the oven and preheat the oven to 325 degrees F. Line two baking sheets with parchment paper. Using a small glass or cookie cutter (1 1/4- to 1 1/2-inch wide), trace 15 circles on each piece of parchment, leaving about 2 inches between each round. Flip the parchment over; the lines will be visible through the paper but you will not have to pipe directly onto the ink. Fit a pastry bag with a round tip about 1/4 inch wide.
Sift the confectioners' sugar and ground almonds into a bowl and discard any larger nut chunks. (If you have more than a tablespoon of bigger chunks, grind those until powdery and then resift.) Combine the egg whites and salt in a large bowl and whip on medium-low speed with an electric mixer until frothy, 1 to 2 minutes. Add the granulated sugar, increase the speed to medium-high and whip until very soft peaks form, 2 to 3 minutes. Add the almond extract and a few drops of food coloring (if using); a little goes a long way so add with caution. Whip until stiff peaks form, 3 to 5 minutes. Fold about one-third of the sugar-nut mixture into the egg whites until blended, and then carefully fold in the remaining two-thirds. The batter should be a bit fluid but not runny. It should slowly drip off the spatula and sit on top of the batter in the bowl for a bit before eventually oozing back into it. If it seems a bit stiff at this point, fold once or twice more until it relaxes, although be careful not to over-fold. This correct texture is the key to the macaron and it is better to have a stiffer batter than a looser one.
Transfer the batter to the prepared pastry bag. Holding the bag perpendicular over the baking sheet, squeeze until the batter fills a circle drawn on the paper. Release the pressure on the bag and pull towards you to prevent a pointy tip on the center of the cookie. Repeat with the remaining circles. Gently flatten any points on the cookies with a damp fingertip.
Firmly rap the baking sheets against the counter to release any air bubbles and let stand at room temperature until the tops of the cookies no longer feel wet, 10 to 15 minutes.
Bake, one sheet at a time, until the macarons are slightly crisp, about 15 minutes. Rotate the sheet halfway through for even baking. Cool the cookies on the sheets 5 minutes, and then peel them off the paper and cool completely on a rack. To assemble the cookies, spread a thin layer of the preserves on the bottoms of half of the cookies, about 1/4 teaspoon per cookie. Top with a second cookie, gently pressing to squeeze the preserves to the rims.