Place a pot filled water - enough to immerse the onions- over high heat and add the cardamom pods and the bay leaves. Bring to a boil.
Meanwhile peel the onions, wash and cut a wedge in each of them, this helps soften the layers.
Add the onions to the pot, reducing heat to medium-high and let it cook for 15 minutes or until the layers are easily separated.
Heat oil in a large skillet over medium heat.
Add chopped onions, saute until translucent about 2-3 minutes.
Add rice, stir to combine for 2 more minutes.
Add tomato paste and the spices then stir everything well.
Add the herbs, stir for 30 seconds, then turn off the heat. Let it cool down for 10-15 minutes.
Transfer to a bowl, add the ground meat and mix well.
Take the onions out of water and let it cool down until you can handle it with your hands.
Separate the layers carefully.
Place 2-3 tablespoons- may be more according to the size of the onion layer- and roll.
Place some of the herbs on the bottom of your slow cooker.
Combine the cooking liquids together and season.
Arrange the stuffed onions in the crockpot and pour the liquids over.
Cook on low for 6 hours.