Crockpot Beef Vindaloo

I'm getting pretty slow cooker obsessed lately. I like the challenge of coming up with recipes that actually benefit from a really long slow braise. I also love breaking the stereotype that Crockpot cooking has to be middle-America dishes made with canned cream-of-whatever soup. This weekend, it was a Crockpot Beef Vindaloo, a classic, piquant, and very spicy meaty curry. It turned out fab in the Crockpot.

Crockpot Beef Vindaloo
cilantro (chop leaves and stems separately, reserve leaves for garnish)
2 onions, roughly chopped
1/2 lb bell pepper, roughly chopped (optional)
2 t minced ginger
6 cloves garlic, roughly chopped
3 lbs stew beef, chopped into bite-sized chunks. Lamb would be delicious instead
black pepper, to taste
salt to taste (I used 2 t)
1 t beef bouillon (optional)
14 oz can crushed tomatoes
1 cup pumpkin puree (This pops up a lot on my blog. It makes a great neutral, healthy thickener for soups and stews)
1/4 cup apple cider vinegar
approximately 1 t sugar or 1 packet Splenda (to round out the flavor)
Curry powder (I like Sun Brand Madras curry powder, and I use 4 T. Depending on the curry powder you use, you may need more or less.)
OR if you'd prefer to make your own curry powder, add all of the following: 
2.5 T cumin
2 t coriander
2 t turmeric
2 t cayenne pepper (This makes a quite spicy vindaloo. Use less if you can't handle it.)
1 t cardamom
1 t cinnamon
1/2 t mustard seeds (sometimes I cheat and just do a squirt of mustard instead)
1/4 t cloves
1 bay leaf

Garnish

Cilantro leaves

Greek yogurt (optional)
Serve with basmati rice or cauliflower "rice"

Dump everything except garnish into slow cooker and stir together. Cook for 7-8 hours on low or 4 on high.