Heat a large pot over low-medium. Once preheated, add the oil and onions. Cook for about 10 minutes, stirring occasionally, until softened and lightly browned. If the onions are browning too much, reduce the heat and add a splash of water if needed.
2 teaspoons oil, 1 medium onion
Add the carrots, garlic, and ginger, and cook for another 10 minutes, stirring occasionally. The carrots should be softened but not cooked through.
3 medium carrots, 2 cloves garlic, 1 thumb ginger
Stir in the curry powder and cook for another minute.
1 tablespoon curry powder
Add the tomatoes, coconut milk, and salt. Rinse the tomato can with a little water from the tap (around 50 ml / ¼ cup) and add to the pot. Increase the heat to bring the curry to a high simmer, then add the lentils. Cover and simmer for 15 minutes or until the lentils are fully cooked.
Taste and season as needed. Serve hot with any toppings or sides you'd like.
Notes
Curry powder: use your favourite. Curry powder is simply a mix of spices commonly used in curries and they vary widely - I like mine to be turmeric-forward. If you want to use individual spices, use 1 teaspoon each turmeric and ground coriander, ½ teaspoon each cumin and ground ginger, and ¼ teaspoon hot pepper.Storage: keep in a sealed container in the refrigerator for up to three days. Reheat as usual. You may need to add a splash of water if reheating in a pot so that it doesn't stick.Freezing: transfer fully cooled curry to an airtight container and freeze up to three months. Thaw in the refrigerator overnight before reheating. It's best to freeze the same day you cook it for freshness.Try add-ins: I recommend adding frozen peas or fresh greens like spinach or chard once the curry is finished cooking. Stir them in and place the lid back on the pot for a couple of minutes before serving. We often add peas and/or greens to this.Simmer until tender: the lentils should need around 15 minutes to cook, but can take a little longer if they're very old. Simmer the curry until the lentils are cooked through even if it takes more than the outlined time.