Sift almond flour and powdered sugar into a large mixing bowl to remove any lumps.

Add almond extract and rose water (if using) to the dry ingredients. Mix well.

If the mixture is too dry, add a lightly beaten egg white to help bind the ingredients.

Knead the mixture with your hands until it forms a smooth, pliable dough. If it's too sticky, add a bit more powdered sugar.

Wrap the marzipan in plastic wrap and let it rest at room temperature for about an hour before using.

Shape the marzipan into desired forms or use it to cover cakes. Store any unused marzipan in an airtight container.