I've posted recipes for this more than once, I think, but here's a better one. We're sorting through all the hassles of moving to Cairo right now so it's nice to remember the good parts too. This version uses the instant pot and also cooks each thing separately so you can layer them. I prefer them cooked separately, but you can do them together, cooking the lentils in plenty of water, then adding the rice after 20 minutes, then the pasta ten minutes later. If you want garbanzos, cook them earlier. The system I use below doesn't get too many pots dirty which is the biggest drawback to the cook everything separately system. You just end up with one extra small pot that needs to be cleaned.
First, slice a bunch of onions (5 is not too many) and saute them till they're caramelized. This takes a long time, but if you start them at the beginning and remember to stir every so often, they'll be ready when everything else is.
Next, get some water boiling for your rice and then start the rice cooking when the water boils. At about the same time, also get the lentils cooking in the instant pot. It's a 2-to-1 ratio of water to lentils and they'll cook for 15 minutes.
You can use lentils, rice, pasta, and/or garbanzos and you can adjust the ratios as you like. A simple option is to do one cup of three different choices. It really doesn't matter. You can also use brown rice and whole wheat pasta. I use garbanzos I cooked earlier because they take longer to cook.
While the lentils are cooking, get the sauce going. Saute lots of garlic in some olive oil, then add some chopped tomatoes. Maybe four plum tomatoes if you don't want much sauce, the way kushary seems to be done now, or more if you want more sauce. I like more sauce so I use more tomatoes. Also add some tomato paste (maybe 1/2 cup for less sauce, and 3/4 cup for more) and a glug of vinegar (3 T for less, more for more). And some salt and cayenne- spicy is good for kushary. Simmer that for 10-15 minutes while everything else cooks.
When the lentils are done, do a quick release, then spread the just-cooked rice on top. If you're using garbanzos, add them for a layer. Then rinse out the rice pot and boil water for the pasta, if you're using it. When the pasta is cooked, drain it and add it for the last layer.
Serve the layered legumes and grains out of the pot with the sauce and onions. Everything (the onions, sauce, and legumes/grains) should all finish at about the same time if you're lucky. The entire process takes about 35-40 minutes if you stay on track.