Place the lentils and 2 whole, peeled garlic cloves in a medium saucepan and stir in the water. Bring to a boil, then reduce the heat to a simmer. Cook, stirring occasionally, until the lentils are very tender, 20 to 25 minutes. Drain any excess liquid and discard the garlic cloves.
Preheat the oven to 375 degrees F.
Transfer 1 ¾ cups of the lentils to the bowl of a food processor. Use the remaining lentils for another purpose.
Heat the olive oil in a medium nonstick skillet set over medium-high heat. Add the onion and cook until light golden brown, 3 to 4 minutes. Chop the remaining 3 garlic cloves and add to the skillet, along with the curry powder and paprika. Cook for 30 seconds.
Transfer the onion mixture to the food processor, along with the brown rice, salt and pepper.
Pulse until the mixture is combined, but not pureed.
Transfer the lentil mixture to a bowl, and stir in the breadcrumbs, lemon juice and cilantro.
Using about ¼ cup per patty, form the lentil mixture into ½-inch thick round patties.
Place a baking sheet in the preheated oven for 5 minutes. Remove, coat with cooking spray and transfer the lentil patties to the baking sheet.
Bake for 15 minutes, or until the lentil cakes are browning on the bottom. Flip and cook for additional 5 minutes.
Serve the lentil cakes with the sauce, and garnish with cilantro, if desired.
Place the roasted red peppers in the bowl of a food processor.
Heat the olive oil in a small nonstick skillet set over medium-high heat. Add the onion and cook until browned, 3 to 4 minutes.
Add the garlic, paprika and curry powder, and cook for 30 seconds.
Transfer the onion mixture to the food processor, along with the vegetable broth, salt and pepper.