Add onion and garlic. Saute 5 minutes or until the onion is soft.
Add broth and next 5 ingredients.
Bring to a boil. Reduce heat to low.
If Using Pressure Cooker or Instant Pot
Add lentils and bring to a boil.
Place the lid on the cooker and bring up to high pressure. Cook for 9 minutes on high (you may need a few more minutes since the tomatoes counteract the cooking of the lentils slightly. Conversely, you could add the tomatoes after cooking the beans and then let the resulting dish cook for a bit).
Let pressure come down naturally. Remove lid carefully.
Stir in basil and salt to taste.
If Using Regular Pot
Add lentils, and then simmer, uncovered, stirring occasionally, approximately 30 minutes or until lentils are tender. (Red lentils will cook quicker than brown or green.)