Wheat is the food. Roti made on a tawa, phulka puffed on the flame, and in winter missi roti of wheat and gram flour with onion and chilli worked into it.
Alongside it, and older in the Malwa, are the millets: bajra and jowar, which need less water and were the staple of the dry districts before canals and procurement made wheat universal. Makki, maize, gives the makki di roti that goes with sarson da saag.
Saag is mustard greens, plus bathua and spinach, cooked down for hours, worked with a wooden ghotna, finished with makki flour and butter. It is the one Punjabi dish everyone outside Punjab knows and it is a winter dish that takes half a day.
Dairy carries the rest: lassi, dahi, paneer, khoya, and ghee used in quantities that shock outsiders. A working farmer eating this food was doing manual labour from before dawn.
Pinni, panjeeri and gur are winter foods made for warmth and for feeding women after childbirth. Gur, unrefined cane sugar boiled in an open pan at a village velna, is still made seasonally in the Doaba and sold by the block.
The Punjabi restaurant food known worldwide, butter chicken and dal makhani, was invented in Delhi in the late 1940s by Partition refugees from Peshawar. It is a refugee cuisine and it is barely eaten in Punjabi villages.
The Punjabi meat cooking that reached the rest of India came through the refugee restaurants after 1947, and the tandoori and the butter chicken were assembled in Delhi in those years.
The older Punjabi meat tradition is the slow cooked one: nihari, paya, siri, cooked overnight and eaten in the morning, and it belonged to the Muslim quarters of the towns.
Most of that went in 1947. What survives on the Indian side is in a few Amritsar and Malerkotla shops and in the memory of families who ate it before the town changed.