Lebanese Lentils, Rice and Caramelized Onions (Mujadara)

INGREDIENTS

• 1 cup brown or green lentils (not lentils du Puy), sorted for debris and rinsed
• Kosher salt
• 1/2 teaspoon cracked black peppercorns
• 1/2 cup extra-virgin olive oil
• Squeeze of fresh lemon juice
• 1/2 teaspoon cayenne pepper
• 1 teaspoon cumin seeds
• 1/2 teaspoon ground cumin
• 3/4 cup basmati rice
• Greek yogurt, for serving, optional
• 2 tablespoons pine nuts, optional
• 3 medium red onions, thinly sliced
• 1 (1-inch) cinnamon stick