In a small saucepan, cover the lentils with cold water. Set over medium heat, bring to a boil, and cook until they are tender - about 10 minutes. Drain and set aside until ready to use.
While the lentils are cooking, add the cumin seeds and mustard seeds to a large skillet. Set over medium heat and cook until the seeds become more fragrant and begin to dance around on the pan - about 2-3 minutes.
Add 15ml (1 tablespoon) of neutral oil to the skillet with the mustard and cumin seeds and heat until shimmering. Add the onion along with a generous pinch of salt. Cook the onion until it has softened and is beginning to brown around the edges, about 7-10 minutes.
Add the ginger and garlic to the pan with the onions. Stir to combine and cook until very fragrant, about 30 seconds.
Add the coriander, turmeric, ground cumin and cardamom. Stir and cook for another minute or so, until very fragrant.
Add the tomato paste to the pan. Stir to combine with the onion mixture and cook for about 2-3 minutes. Remove the pan from the heat and set aside.
In a large bowl, whisk together the eggs and lemon juice, along with a couple generous pinches of salt. Add the cooked onion mixture and stir to combine.
To the bowl, add the drained lentils along with the garam masala and cilantro. Stir until well combined. Sprinkle the bread crumbs over the lentil mixture and fold them in until just incorporated.
Evenly divide the lentil mixture into 4 balls. Press them into patties with your hands and set aside.
Over medium heat, add 15ml of neutral oil to a large skillet. Heat until shimmering and add your patties. Cook for five minutes before flipping and cooking for another five minutes. Serve immediately.
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Notes
If you're sensitive to heat, remove the ribs and seeds from the chiles to make it less spicy.