Directions:

Cream the butter with a paddle attachment then mix in the sugar.Add the egg whites gradually and then mix in the vanilla and lemon extracts.Add the flour and mix until just incorporated.With a small (1/4-inch) plain tip ....I used a plastic bag and cut off the tip (about 1/2 inch).Pipe 1-inch sections(I thought they would be too small so I made them close to 2 inches) of batter onto a parchment-lined sheet pan, spacing them 2 inches apart as they spread.Bake in a preheated 350 degree oven for 10 minutes( this was too much...I noticed mine took about 6-8 minutes) or until light golden brown around the edges. Keep an eye on them! Let cool on the pan.Cookie Filling: In a small saucepan over medium flame, scald cream. Pour hot cream over chocolate in a bowl.Whisk to melt chocolate, add zest, extract and blend well.Set aside to cool (the mixture will thicken as it cools). Spread a thin amount of the filling onto the flat side of a cookie while the filling is still soft and press( or place gently) the flat side of a second cookie on top. I used a plastic bag to hold the filling and cut of a small hole at the tip of the bag. I then squeezed some filling on the cookie. This minimizes the mess of spreading it on the cookie. It is much cleaner.Repeat with the remainder of the cookies.