Method

1. Place the almonds and 1/2 cup of the confectioners' sugar in a large, 7-cup food processor fitted with a steel blade. Process the nuts and sugar until the nuts are very finely ground, stopping periodically to scrape the sides of the processor bowl. The sugar will help prevent the nuts from turning into almond butter, but still be careful about overprocessing.
2. Once the almonds are very finely ground, add the rest of the confectioners' sugar and pulse until it is completely mixed into the ground almonds.
3. Stop the processor and add the egg white and the almond extract, if using.
4. Turn the processor back on and process the almond paste until it comes together to form a clump.
5. If it seems very sticky, add a little more confectioners' sugar, a spoonful at a time, until it is smooth.
6. You can use the almond paste at once or wrap it to use at a later date. If keeping for future use, form into a log and wrap well in plastic wrap.
7. Store in a zip-top bag in the refrigerator or freezer.