Heat oil in 12-inch skillet over medium-high heat until hot. Add onions to the skillet and cook until softened for 5 to 7 minutes.
Add ALL spices to skillet, stirring and fully coating onions for about 60 seconds. Remove from heat and transfer cooked onions into slow cooker.
In addition to your seasoned onions, add in yellow split peas, potatoes, water, broth (stock), coconut milk, and squeezed lime into the slow cooker.
Cover and cook on high for 5- 6 hours until peas are tender or 7-8 hours on low. You can check midway to adjust seasonings to your liking. Your peas will "split" and your soup will be of a puree texture.
Once done serve with your choice of rice, naan bread, or additional veggies.
I have used Chana Dal instead of yellow split peas for this recipe and it worked out perfectly. Chana Dalholds it shape more than yellow split peas. Use that in your soup if you prefer more texture. Read Difference between Chana Dal & Yellow Split Peas to learn more.
To save time on all the spices, outside of the salt and pepper, you can use a store-bought curry powder.If you go this route, the flavor profile will be different depending on the brand you use. You would need to taste test this as you go.
Sweet potatoes or carrots can substitute for white potatoes.
Russet potatoes can be substituted for golden potatoes or even red potatoes.
Feel free to add green additional veggies to this soup like spinach or kale. NOTE: If doing this add in during the last hour of your cook time in your slow cooker.
I would NOT substitute the coconut milk as it really helps bring out the flavors of the dish. Use full-fat can coconut milknot the one in a jug.
Leftovers keep covered in the refrigerator 3 to 4 days and can be frozen for up to 1 month in an airtight covered container or large freezer bag.