In a medium saucepan, combine 1 cup of red lentils with 2 cups of water. Bring to a boil over medium-high heat, then reduce heat to low and cover. Simmer for 10-12 minutes, or until tender. Drain excess water and cool slightly.

In a large mixing bowl, combine the cooked lentils with grated sweet potato, chopped onion, and minced garlic. Add cumin, paprika, and ground coriander. Mix well.

Add the chopped cilantro and half a cup of flour to the mixture, stirring until combined. Let the mixture rest for 5-10 minutes.

Heat olive oil in a skillet over medium heat. Form lentil mixture into patties, about 2-3 inches wide. Fry patties for 3-4 minutes on each side until golden brown and crispy.

In a blender, combine avocado, cilantro, minced garlic, lime juice, and yogurt. Blend until smooth, adding water if necessary for consistency.

Serve warm patties drizzled with creamy avocado sauce or on the side for dipping.