I experimented with a lamb curry today. Here's what I did:
Marinade 500gms of lamb overnight in a coarse paste of 1 medium red onion, 10 cloves of garlic, 5 cms of garlic, 3 tbs Madras curry powder, and 1 tbs of Kashmiri chili powder, all blitzed in a mini food processor:

Heat 3 tbs of ghee in a pan and add 3 black cardamom, 2 sticks of cinnamon, and 2 bay leaves:

Fry the lamb along with the marinade for about 30 mins till the mix is relatively dry:

Add 1tsp of cardamom seeds and 6 cloves powdered, and continue to saute for 10 mins. Add 1/2-cup of tomato puree and salt to taste. Add 3 cups of water. Bring to boil, cover with lid, and simmer for 90 minutes.

Add a couple of handfuls of pieces of butternut squash. Add a couple of handfuls of spinach leaves. Add a paste of 1/4-cup of heavy cream, 6 cashews, and 2 tsps of poppy seeds. Add couple of pinches of garam masala, adjust salt, and cook for 5 mins to finish.

The curry had a wonderful aroma, but had a very slight bitter after-taste. I added a touch of honey and salt, and that took care of the problem.
Why did the curry have a bitter after-taste in the first place? I don't think I burnt anything. I was reading somewhere that blitzing the onion in a processor instead of finely chopping with a knife, can make a curry bitter. Any thoughts or advice?
Thanks as always!