These classy sandwiches of pistachio and meringues are as delicious to make as to present.
Combine half a cup flour and the pistachios in the bowl of a food processor fitted with a metal blade. Process until the nuts are finely ground but not pasty.
Add the remaining flour and salt, and process until well-combined. Set aside.
Measure out one and a half tablespoons beaten egg yolks and combine with the water in the mixer. (Discard the remaining yolks or save for another use). Beat two to three minutes on high speed, or until fluffy and lemon-colored. Gradually add the sugar while beating.
Then add the margarine, a few tablespoons at a time, and beat until well-blended. Scrape down the sides of the bowl as needed to ensure even mixing.
Gradually add the pistachio-flour mixture, blending until evenly incorporated.
Divide the dough into two equal parts and flatten each portion into a disk. Wrap in plastic and refrigerate for one hour or until firm enough to roll without sticking.
Preheat oven to 350°F.
Working with one disk at a time, on a lightly floured surface, roll the dough to a 1/4 inch thickness.
Using a one- and- a- half-inch round cookie cutter, cut circles from the dough. Transfer the circles to the lined cookie sheet. Bake the cookies for 11–13 minutes, or until lightly browned. (You can also make circles with your hands and flatten with the bottom of a glass.)
Optional: Once the cookies are cooled, top them with the raspberry jam. Place a rounded 1/4 teaspoon jam in the top center of the cookie and spread it around the cookie surface, making sure to leave the edges of the cookie clear.
Turn the oven down to 325°F and reline the cookie sheets.
Preheat the oven to 375°F. Line 2 cookie sheets with parchment paper.
Place the egg whites, lemon juice, and salt in a clean bowl of the mixer. Beat on medium speed to form soft peaks.
Gradually add the powdered sugar, stopping to scrape down the sides of the bowl.
Turn the mixer to medium-high speed and continue to beat until the mixture is glossy and thick, about 7 minutes. The meringue will not hold stiff peaks but it should hold tracks from the beaters. Add the food coloring, if desired.
To assemble the meringue layer, it’s important work quickly; otherwise the meringue will deflate.
Fit a pastry bag with a small round tip and fill the bag with the meringue.
Pipe the meringue over the pistachio cookies. You may form circles in the center of each cookie, or concentric circles covering the surface. To achieve an effect of height, start at the outer border of each cookie and pipe circles in an inward motion, gently releasing with swirl in the center.
Bake the cookies for additional 8 minutes, until meringues are dry but minimally discolored. Do not overbake the meringues, as they may crack and separate from the cookies.
For an added treat, pipe any leftover meringue into disks and bake as directed above.