The Muslim Konkani Kadam family runs a restaurant in Mumbai. As a child, the second-oldest son, Hassan, would shop with his mother at the market, where he was adept at picking the highest-quality food. Now a young man, he is in training to replace her as the restaurant's main cook. When a mob attacks and burns down the restaurant after a disputed election, his mother dies in the fire. Seeking asylum in Europe, the Kadams first settle in London, but they dislike the climate and their house, which is right next to Heathrow, so they depart for mainland Europe.
Near St. Antonin in the Midi-Pyrénées in France, the brakes on the Kadams' van fail. Marguerite, a local woman, passes by and helps tow the van to town. She invites the family into her apartment while they deal with the auto repair shop and arrange lodgings for the night, and she treats them to a tray of delicious food she made using fresh, local ingredients.
The next morning, Hassan follows his father, Abbu, to an abandoned property they passed the night before. A restaurant had been there, but it failed because Le Saule Pleureur ("The Weeping Willow"), an upscale French restaurant with a Michelin star, is located just across the street, a hundred feet[c] away. Abbu buys the land anyway, as he is confident the Indian food Hassan will cook for their restaurant will attract customers.
Naming their restaurant Maison Mumbai, the Kadam family renovates the property. One day, Madame Mallory, the proprietor of Saule Pleureur, visits and asks to see their menu. Abbu hesitates, but Hassan gladly gives it to her in case she wishes to dine with them sometime. When she buys all of the ingredients the Kadams need from the local market on the day of their grand opening, a war of sabotage and complaints to the mayor of the village erupts between Abbu and Mallory. While this is going on, Hassan asks Marguerite, who is a sous chef at Saule Pleureur, to help him learn about French cooking, and they develop feelings for each other.
The war between the restaurants peaks on Bastille Day, when one of Mallory's chefs, Jean-Pierre, and two others spray-paint "La France aux Français" ("France to the French") on the outer wall of Maison Mumbai and firebomb the covered outdoor eating area. Hassan catches them in the act and scares them off, but his hands get burned. Mallory, deducing who is responsible, dismisses Jean-Pierre and personally scrubs the graffiti off the wall. While she is cleaning, Hassan offers to make her an omelette, which is how Marguerite said Mallory interviews potential chefs. As his hands are bandaged, Hassan instructs Mallory how to make the omelet his way, which uses unusual spices and ingredients. She is so impressed by the result that she invites him to work at Saule Pleureur so he can get a more classical training to supplement his natural ability. Abbu is initially against the move, but ultimately allows Hassan to go.
Marguerite accuses Hassan of using her to help him get his new position, and they compete for Mallory's approval in the kitchen. Hassan outshines Marguerite, and his cooking, which evolves into a unique French-Indian fusion, results in Saule Pleureur receiving a second Michelin star. The award gets him national attention, and he accepts a job at a fancy Parisian molecular cuisine restaurant. While he is gone, Abbu and Mallory begin seeing each other.
In Paris, Hassan's style quickly draws attention, and there is speculation that he may bring his new restaurant a third Michelin star. Over time, however, he becomes increasingly lonely and distracted by thoughts of his family and Marguerite, so one day he returns to St. Antonin. He tells Marguerite he has a business proposition for her and asks her to help him cook a dish he has not made for a long time. They prepare it in the kitchen at Saule Pleureur, and, when the Kadams and some friends arrive for dinner, everyone is surprised to see Hassan. Mallory announces she is giving him control of Saule Pleureur, and he says he is moving back to the village to run the restaurant with Marguerite. Hassan does not answer the call that will reveal whether the restaurant in Paris received a third Michelin star, saying he will earn a third star with his friends and family. The group carries their meal across the road to eat at Maison Mumbai.
Helen Mirren as Madame Mallory
Om Puri as Abbu "Papa" Kadam
Manish Dayal as Hassan Haji Kadam
Rohan Chand as Hassan Kadam (7 years old)
Charlotte Le Bon as Marguerite
Amit Shah as Mansur Kadam
Farzana Dua Elahe as Mahira Kadam
Dillon Mitra as Mukthar Kadam
Aria Pandya as Aisha Begum Kadam
Michel Blanc as Mayor
Clément Sibony as Jean-Pierre
Vincent Elbaz as Paul, manager of the Parisian molecular cuisine restaurant
Shuna Lemoine as Mayor's Wife
Juhi Chawla as Ammi "Mama" Kadam (guest appearance)
from a screenplay written by Steven Knight, adapted from Richard C. Morais' 2010 novel of the same name.