Add the ras el hanout and capsicum and cook another few minutes, then stir in the lentils.
Add the tomato passata and the stock, bring to the boil, then lower to a simmer. Cook for about 30 minutes.
Remove from heat. Cool for about 10 minutes, then puree with a handheld blender. Season to taste. If the soup tatses a little bitter, add the maple syrup. Serve immediately.
Notes
The soup will keep in an airtight container in the fridge for up to 3 days. it is suitable to freeze.