Preheat the oven to 350 degrees.
Cream the butter and sugar together.
Add the egg, almond extract and chopped almonds (or pecans). Mix well to combine.
Add the salt, flour and optional cardamom (if using), and mix in to the egg and almond mixture.
Scoop the Sandbakkel dough out by the tablespoon full and roll into small balls (about 1 inch balls).
Place each Sandbakkel dough ball into a Sandbakkel tin, and press evenly throughout the tin. Note: Be sure to avoid getting the dough going over the Sandbakkel tin edge, as it will be hard to get out.
Place all the Sanbakkel tins with the dough inside on a rimmed baking sheet.
Bake in the preheated oven for 15 minutes, or until the dough is a golden color around the edge of the tins.
Remove the baking sheet from the oven, and let the cookies cool in their tins for 1 - 2 minutes.
To remove the Sandbakkel cookies from their tins: While the tins are still warm (be careful!), flip them upside down and tap them (a little forcibly) one by one onto a plate. The Sandbakkel should separate from its tin. Continue until all the Sandbakkels are out of their tins. Note: Removing the Sandbakkels from their tins like this can be done when the Sandbakkels are fully cool, but it is much harder and requires a little more force to get them out).
Serve and enjoy with a hot cup of coffee, tea, or hot cocoa!