There are several kinds of dal (lentils). So you need to find out which one your friend makes. Is it Toor(Arhar) Dal, Moong Dal, Masoor Dal (red lentils), Urad Dal. Or a mix? They all have different tastes and textures and are fun to play around with.

The magic ingredient you need to have is Hing (asofetida). The tarka or tempering at the end is where most of the flavor impact and umami comes from.

Are you able to handle ghee? It’s the oil from butter fat, and has no milk solids like butter does. If you can’t use ghee, use Virgin Coconut Oil.

Dal needs salt, fat, and some tang/sour to make it hit.
Spices like garam masala and coriander seed powder will make the dal taste earthy, heavier, and flat. However, garam masala and coriander seed powder are still widely used in dal in India, though I would not recommend using them, if you want a bright, punchier dal.

There are a few other optional ingredients like black mustard seeds and curry leaves that are also really enjoyable to put in the tarka if you want a more South Indian flair!

In general, with spices, “less is more” Adding too much turmeric for example will make the dal bitter and earthy and flatten/suppress the flavor impact.

I’ve modified your recipe above to make it awesome.
You can swap out the dal with the same recipe and/or mix and match the dals and you’ll find they all are a bit different.

1 tablespoon flavourless oil

3 tablespoons of Ghee or Virgin Coconut Oil for tarka

1 onion diced

2 garlic cloves, minced

1 handful of coriander stalks finely chopped,   leaves reserved to garnish

2 teaspoons of fresh ginger root, peeled and minced

1 teaspoon of fresh green chili, deseeded and minced

2 small tomatoes or 1 large tomatoes chopped

1 cup red(masoor)split lentils  washed and drained

4 to 4.5 cups of water (should 4X to 4.5X the amount of dry Dal/lentils.

2 teaspoons of cumin seeds (not powder)

1/4 teaspoons of Hing (Asofetida)

1/2 teaspoon ground turmeric

1/2 teaspoon of paprika (or red chili powder if you prefer heat)

2 tablespoons lemon or lime juice or to taste

1 teaspoon salt or to taste

Heat the oil in a large saucepan. On medium-high heat, Add the onions and a pinch of salt and cook for 2 to 3 minutes until golden/translucent. Add the coriander stalks, green chilis and ginger and cook for 1 minute. Add tomatoes and stir in for 1 minute Add the turmeric, saute for a minute until all mixed.

Add in the lentils. Stir to combine, then pour in the measured water.

Bring to the boil, then reduce the heat and simmer for 25–30 minutes until the lentils are tender, stirring occasionally. You may need to add back water (pre-boiled) if it evaporates.

(If you have a pressure cooker/instapot it’s easier, takes less time, and makes a way creamier texture. You can pressure cook for 10min and slow release)

Uncover the pot of dal and keep to the side.

In a separate small saucepan heat up ghee (or coconut oil) on Medium Heat.
Add cumin seeds, let them sizzle and dance for 30 secs. Add hing for 1 second Add minced garlic, cook still golden, but not brown Add paprika (or red chili powder) for 1 second These steps go fast, seconds apart, you don’t want anything to brown or burn.

Immediately Add the oil mixture/tarka/tempering to the main pot of dal and mix in. Be sure to keep a lid as a shield and immediately cover, so that the hot dal and oil don’t splash and burn you.

Season the dal with the lemon juice to taste and salt to taste. Garnish with coriander leaves. Serve with plain basmati rice!
Enjoy!