Crunchy, chocolaty and so good that you'll want to make and eat them even if/when you're not celebrating Passover. They are a sandwich cookie featuring two lacy, thin sides with dark chocolate in the middle.
Combine the farfel, matzo cake meal, sugar, salt, and ground almonds or almond meal. Mix until well combined.
Add the melted butter (or margarine.) Mix the melted butter or margarine into the dry ingredients and then add the egg and extract(s). Mix again to make a slightly loose batter.
Add the chopped or crushed almonds and mix again. At this point, the dough is gloppy. Chill the dough in the refrigerator or freezer for 15-30 minutes, until the dough is stiff.
Preheat the oven to 325 degrees F. Line 2 half sheet pans with parchment.
Using two teaspoons or your hands, portion out small balls of dough, less than 1-inch in diameter. I prefer to put my dough in the freezer so it gets fairly stiff. Then, I use my hands to make neat balls, but you really cannot guarantee that they will retain their perfectly round shape during baking.
Set on the baking sheets about 2-inches apart. Bake for 8-10 minutes, until the edges are a deep golden brown. Watch carefully as the cookies burn easily. (See note)
Once the cookies are fully baked, let them sit on the pan for at least 5 minutes to cool down. While they are cooling, melt the chocolate, either carefully in the microwave, or by placing the chocolate in a double-boiler on the stove. (In the top of the double-boiler, the chocolate never touches the water or the direct heat.) Stir occasionally until the chocolate is fully melted and glossy. (See note.)
Once the cookies are cool, using a pastry brush, brush the wrong (flat) side of one cookie, then another and gently press them together. I like to add a tiny extra dab of chocolate in the middle of one of the flat sides to assure a good seal, but that's not absolutely necessary. Put the cookies on a wire rack to dry and let the chocolate harden. (See note.)
I like the extra almond kick that the extract provides. However, it is optional as the cookie has plenty of flavor even without it.
If you bake one pan at a time, they will be done in less time- probably closer to 8 minutes than 10. If the ones in the back are getting brown before the ones in the front, open the oven and quickly rotate the pan.
To make a full batch using 2 pans you will need to use each pan twice. Cool the pan down between each use. You can do this by taking off the parchment and running the pan under cool water, then drying it before replacing the parchment. (Parchment can be re-used for the second go-round.)
Here is an explanation for how to create a double-boiler to melt the chocolate
Once you put the chocolate between cookies and leave them on a wire rack, they may need at least an hour or two for the chocolate to harden, sealing the cookie "sandwich." How long it takes depends in part on how hot your kitchen is and how thick the chocolate layer inside the sandwich.