Heat 2 Tbsp. of the oil in a large saucepan over medium heat. Add almonds and garam masala spice; cook 2 to 3 minutes, stirring often, until almonds are golden brown. Transfer to a plate.
Add remaining 2 Tbsp. oil and onion to pan. Cook 6 to 7 minutes, stirring frequently, until softened. Stir in garlic, salt, red pepper flakes, tomato paste, and curry powder. Cook 2 to 3 minutes, stirring often, until garlic is aromatic and tomato paste is caramelized. Stir in lentils; cook 1 minute.
Pour in broth and coconut milk and bring mixture to a boil. Reduce heat to medium-low, and simmer for 25 minutes, until lentils are softened. Add a dash of water if soup needs thinning.
Ladle soup evenly into each of four bowls. Stir in a dollop of coconut milk yogurt and garnish with cilantro leaves and garam masala almonds.