French Onion Flavour, Fully Shack Loaded

The French Onion limited-time menu is here, and everything you love about rich, comforting flavour, done the Shack way!

Burger Me Up… French Onion Style

Crispy shallots, gooey Emmental, caramelised onions… yeah, the menu’s starting strong.

The French Onion Burger is a proper flavour bomb. A juicy cheeseburger topped with gooey Emmental cheese, golden caramelised onions, crispy shallots and rich roasted garlic mayo. Savoury, melty and deeply satisfying from the first bite to the last.

Feeling extra? The Double French Onion Burger doubles down with two beef patties, more Emmental and even more onion-packed goodness. Bigger burger. Bigger grin. 

A Melty ‘Shroom Moment

Meat-free but still bringing serious flavour.

The veggie French Onion ’Shroom features a crisp-fried portobello mushroom filled with a molten blend of cheeses, topped with caramelised onions and roasted garlic mayo. Rich, indulgent and every bit as satisfying.

Stack Attack: French Onion Edition

Why choose when you can have both?

The French Onion Shack Stack brings together a juicy Emmental cheeseburger and our iconic ’Shroom Burger, layered with caramelised onions and roasted garlic mayo. It’s tall, bold and unapologetically indulgent. Two hands recommended…

Fries Worth Talking About

These sides aren’t taking a back seat.

Our Roasted Garlic Mayo Fries load crispy crinkle cuts with roasted garlic mayo, parmesan and spring onions. Salty, savoury, and dangerously snackable. Sharing is optional.

And yes, Onion Rings, the fan favourite, are still doing their thing. Beer-battered, golden, and served with tangy sour cream & onion sauce. Because when onions are the star, you commit.

Something Bright on the Side!

All that rich, melty, goodness calls for something refreshing. 

Meet the Pineapple & Mint Lemonade – a vibrant mix of pineapple purée, cooling mint, and our house-made lemonade. Tangy, fresh, and perfectly balanced.

Save Room for Something Sweet

To finish, go all in…

The Chocolate Churros Shake blends cinnamon churro frozen custard with spiced dark chocolate sauce, whipped cream and crunchy chopped churros. Sweet, creamy and fully loaded dessert energy.

Here for a Limited Time 

The French Onion Menu  available from 26th February to 20th May 2026, bringing rich, savoury comfort to every bite. Swing by your nearest Shack or order online* while it’s stacking, melting and sizzling its way through the menu.

Tag us when you tuck in – we want to see the cheese pulls, the burger stacks, and  your full french onion favourites.  #ShakeShackUK

*Please Note: The French Onion Menu is available for delivery from 5th March 2026