Summarize:

In small quantities, Marmite can give soups, stews, and other hearty liquid dishes a rich, savory flavor (and also works great as a browning agent). For instance, try mixing a spoonful of Marmite into a pot of French onion soup in place of beef stock the flavor of the finished soup goes great with bread and cheese, just like ordinary Marmite. In general, you can usually get away with substituting Marmite mixed with water, your favorite vegetables, and a little oil for beef broth. This can allow you to make great-tasting vegetarian versions of all your favorite carnivorous soups and stews. Many Marmite fans agree: the spread pairs deliciously with a wide variety of cheeses. Sharp cheddar is an especially great choice the salty, yeasty flavor of the Marmite enhances the "sharpness" of the cheese, making for a bold-flavored (but tasty) combination. Try adding a few slices of cheese to standard Marmite and butter toast for a satisfying breakfast. Though it may sound odd, Marmite can be a tasty ingredient to include in glazes and sauces for meat dishes. Used correctly, Marmite can give the outer "crust" of roasted meats, poultry, and seafood a rich, distinct "umami" (savory) flavor. Try painting a light mixture of melted butter and Marmite over a whole roasted chicken for a savory treat you should only need a spoonful or two to cover it. If you use Marmite as a meat glaze, you may want to forego sprinkling salt from the salt shaker on your meat, especially if you need to be careful about your sodium intake. Marmite has a very high salt content it's more than 10% salt by mass! Believe it or not, some people not only eat their spaghetti with Marmite they love it. If you're willing to experiment, try adding a half teaspoon of Marmite to al dente noodles along with a small helping of olive oil! You may want to avoid using fine tomato sauces or cheeses to top your dish until you're positive that you enjoy it! Note that some fans of this recipe describe the flavor as being similar to the British snack food "Twiglets".
Add Marmite to soups and stews for savory flavor. Pair Marmite with cheeses. Use Marmite as a glaze for roast meats. Use Marmite sparingly on spaghetti.