Spiced Black Lentils with Yogurt and Mint

Name: Spiced Black Lentils with Yogurt and Mint
Ingredients: 1/2 teaspoon coriander seeds, crushed; 1/2 teaspoon cumin seeds, crushed; 1/2 teaspoon mustard seeds; 2 tablespoons olive oil plus more; 1 small onion, finely chopped; 2 garlic cloves, finely chopped; 1 cup black beluga lentils; 3 cups (or more) low-sodium vegetable broth or chicken broth; 1 teaspoon red wine vinegar; Kosher salt, freshly ground pepper; 0 freshly ground pepper; 1 cup plain Greek yogurt; 1/4 cup fresh mint leaves, thinly sliced