Rinse the yellow lentils under cold water until the water runs clear to remove excess starch.
Heat the extra virgin olive oil in a large pot over medium heat and add the cumin seeds, toasting until they begin to sizzle and smell fragrant.
Add the chopped yellow onion, minced garlic, and grated fresh ginger to the pot, sautéing for 5 minutes until the onion is translucent.
Stir in the diced tomatoes, ground turmeric, sea salt, and black pepper, cooking for another 2 minutes to meld the flavors.
Add the rinsed lentils and water to the pot, then bring the mixture to a boil.
Reduce the heat to low, cover the pot, and simmer for 20 to 25 minutes until the lentils are tender and have reached a thick, creamy consistency.
Stir in the fresh spinach until it is just wilted and remove the pot from the heat.
Divide the dal into bowls and top each serving with a generous portion of non-fat Greek yogurt before serving.