Classic spinach dip's got nothing on chard dip. Made the same way and good served cold or hot and bubbly. Of course you can substitute spinach if you want to but...
Heat a glug of neutral oil in a large frying pan and sweat the onions with a big pinch of salt until they are deeply caramelized and golden brown. Remove from the heat and let cool
In a food processor, blend the chard leaves and the sour cream with the paprika and salt until chunky but well combined
Add the onions, taste and adjust seasoning as desired, and serve with a big platter of raw and roasted vegetables for dipping