The British Ingredient You Should Use In Your Next Shepherd's Pie

Few dishes say cozy comfort food as eloquently as shepherd's pie. What could be better than fluffy mashed potatoes, well-seasoned lamb — not beef, the key difference between shepherd's and cottage pie — and a load of veggies to balance some of the heaviness from the spuds? While the dish is simple enough to prepare, there's one ingredient you may have never used before that can take it to the next level, according to ButcherBox chef-in-residence, Ashley Lonsdale: Marmite.

What is Marmite, you ask? A fair question for us west-of-the-pond residents. Invented in the U.K. in 1902 by the same man who developed bouillon, Marmite is a thick, highly salty spread made from the yeast byproduct leftover from brewing beer, similar but not quite the same as Vegemite. Vegemite has a touch of bitterness, but Marmite has a hint of sweetness to balance the flavor. "Marmite adds a bundle flavor, namely a savory quality, to shepherd's pie thanks to glutamic acid, which is also found in other savory things like soy sauce and mushrooms," Lonsdale told Food Republic. 

Glutamate is a non-essential amino acid often found in protein-rich foods like meats, seaweed, and cheeses like parmesan. Readers might recognize the word from its most famous application: monosodium glutamate, or MSG, which shouldn't turn you off, despite its reputation — after all, the biggest myth about MSG is rooted in racism. While Marmite can be enjoyed as a standalone spread, like MSG, it serves as a flavor enhancer when added to meat — like lamb in a shepherd's pie.

Given that it's such a powerful flavor, Ashley Lonsdale advises to start with ½ teaspoon of the spread to start, and to adjust as needed. "It's easy to taste and adjust the levels as you go," she told us.

As important as knowing how much Marmite to use is knowing when to use it. "I like to add Marmite while I'm building the flavors of the gravy," Lonsdale said. "So as the tomato component develops, a little marmite will help to boost the umami and complexity in the filling." Like Marmite, tomatoes are naturally high in glutamate; adding the Marmite during this step can supercharge the rich flavor.

When it comes to how Marmite, Worcestershire sauce, and soy sauce interact and inform the dish, she explained that while all three add savory flavor: "Each adds it in its own nuanced way since each is made from a different source. Soy sauce is not as sweet as Marmite or Worcestershire." Worcestershire sauce also contains fish, so if you're cooking for someone allergic to fish, Marmite is one of the secret keys to the best shepherd's pie, covering similar flavor profiles while eliminating the allergen.

Chef Lonsdale's final piece of advice is to not rely on the quantity of flavors but to focus on making each element delicious in its own right. "Never rely on the sum of the parts to be the merit of the dish. Each component should be delicious on its own to create a really great shepherd's pie. Season the mashed potatoes well, ensure there's enough richness, and give yourself enough time to reduce and concentrate the flavors of the meat and sauce before baking."