Bring medium saucepan of water to a rapid boil and add tangerine slices. Boil 1 minute, then place slices in the bowl of ice water until cooled. Drain.

In large skillet over medium heat, bring sugar, honey and water just to a boil. Add in tangerine juice and cardamom pods. Heat until sugar dissolves, stirring occasionally. Turn heat to medium-low and place tangerine slices in the sugar-water. Simmer gently—do not boil —45 to 60 minutes, or until rinds are slightly translucent. Carefully stir every 15 minutes or so.

Use tongs to transfer the tangerine slices onto a cooling rack and sprinkle with sugar if you prefer them less sticky. Strain and reserve the liquid to use later. Allow candied slices to cool completely and dry out overnight. These can be used immediately or stored in an airtight container at room temperature for up to 1 month.

The reserved tangerine syrup can be used for the olive oil cake. If you have any leftover syrup, it can be kept up to 1 month in the refrigerator and used for another purpose.