Tomato Lemon Rasam

Name: Tomato Lemon Rasam
Ingredients: ½ cup toor dal (split yellow pigeon peas); 1 teaspoon turmeric powder, divided; 2 teaspoons cumin seeds; 2 teaspoons coriander seeds; 1 tablespoon freshly cracked black pepper; 1 (2-inch) piece fresh ginger, peeled and finely chopped; 1 Serrano chile, chopped; 4 large cloves garlic, chopped; 1 teaspoon vegetable oil; 1 teaspoon yellow mustard seeds; 15 curry leaves, torn into pieces; 1 (14.5-oz.) can chopped tomatoes; ¼ teaspoon asafoetida; ½ teaspoon kosher salt; ¼ cup fresh lemon juice (from 1 lemon); ½ cup chopped cilantro