• Preheat oven to 350° F/175° C.

Cookies

• In a mixer with paddle attachment cream the butter and the sugar.
• Add the egg whites gradually and then mix in the vanilla and lemon extracts.
• Add the flour and mix until just well mixed. Don’t over mix.
• Fit the decorating tip onto a corner of the plastic bag, snip the corner, and attach the coupler. Fill the bag with the cookie batter. Pipe 1-inch (2.5 cm) sections (I made mine longer, about 2 inches/5 cm) of batter onto a parchment-lined sheet pan, spacing them 2 inches/5 cm apart as they spread.
  
• Bake in preheated oven for 10 minutes or until light golden brown around the edges. Let cool on the pan. Continue with the remaining cookie batter.
  

Chocolate Filling

• While waiting for the cookies to cool, in the small saucepan over medium flame, scald the cream.
• Put the chopped chocolate into the medium mixing bowl and pour the hot cream over the chocolate. Whisk to melt chocolate, then add the orange zest and blend well.
• Set aside to cool. The mixture will thicken as it cools.

Assemble

• Spread a thin amount of the filling onto the flat side of a cookie while the filling is still soft and press the flat side of a second cookie on top. Continue with remaining cookies and filling.