Soak the split peas overnight or at least 2 hours in warm water, drain and rinse.
In a deep pan, add oil, add onions, ginger and garlic and cook stirring occasionally, until translucent.(add chopped Serrano or Jalapeno if using)
Add the turmeric and mix well.
Add rinsed split peas, salt, pepper and water. Mix, cover and bring to a boil on medium heat.
Reduce heat to low and simmer, partially covered for 35-45 minutes or until peas have softened to your desired consistency. Taste and adjust salt and spice if needed.
Or use a Pressure cooker: Pressure cook for 1 whistle on high and then on low for 15 minutes. ( Pressure cook for 8 to 10 minutes after the pressure is reached for electric pressure cooker, then natural release). The pictures are of the pressure cooked stew.
Mash the peas if desired. Add some lemon juice if desired and serve. Tastes best with a sour flat bread like Injera.