Brush the inside of your slow cooker with butter and line with parchment. Brush the paper with parchment.
In a bowl, combine the warm water, yeast, and honey and stir. Let sit until foamy, about 5-7 minutes. Stir in the flour and salt.
With an electric mixer, beat the mixture on medium for 5 minutes. Let sit 10 minutes.
Meanwhile, in a small bowl combine the butter, sugar, brown sugar, cinnamon, and cardamom until smooth.
Preheat your slow cooker on HIGH. Turn the dough to a lightly floured surface and roll into a 9x13-inch rectangle. Sprinkle the dough with the cinnamon mixture, and starting from the long end, roll into a log. Slice the log into 12 pieces.
Place the rolls, cut side down, in the cooker. Then wrap the top of the slow cooker with a towel to catch the condensation. Cover and cook 1 hour. Lift up cooker insert and rotate 180º. Cook 30 minutes more. Remove from slow cooker and place rolls on a wire rack.