Grind cashews and almonds into fine powder.
In a non stick pan on medium heat, add sugar and ½ cup of water. Bring to a boil and simmer until the mixture thickens a little bit, about 3~5 minutes.
Add the ground nuts and mix well; keep stirring the mixture until it starts to pulls away from the pan, this will take about 5-7 minutes. Add the ground cardamom, ghee (if using) and mix well. Turn off the heat and let the mixture cool for 5 minutes.
While the mixture is still warm, remove into a bowl and knead to form a smooth and glossy dough.
Roll the dough into a tin sheet and cut the katlis into desired shapes. Katli can be stored in an airtight container for up to 10 days.