What was the food, why did Esav call it “the red, red (substance)”, and why was he willing to trade his birthright for it?
The text does not specify what food it was. Targum Onkelos merely says Yaakov was cooking a dish.
Tradition identifies it as soup made of red lentils.
In this case there was a strong, savoury smell, which a tired and hungry Esav saw as his salvation.
There is a rabbinic view that Abraham had just died and Yaakov was preparing the customary mourners’ meal of round ingredients, suggesting that life rolls around and moves from joy to sorrow.
It fits in with what we know of Yaakov’s character that he did not engage in demanding physical effort but was studious and domesticated and spent time in the kitchen.
But Esav didn’t say “soup” or “lentils”, merely “red, red”: it was the colour that attracted him.
By a play on words, the Torah says that because of this incident Esav became known as Edom, “the red one”.
The moral of the story seems to be that Esav was not a sound thinker who worked out things logically.
He was a man of impulses whose whole life depended on a sudden flash of colour. He probably lived to regret his impulsiveness and what it cost him, but in the long run Yaakov was better fitted to be the leader.