Basil is a versatile herb when used in moderation. It can brighten up a large number of savory dishes, especially those that include tomatoes. As with most herbs, its qualities can quickly become drawbacks when it is used in excess. Too much basil can make your food bitter and unpalatable. If you have gone overboard with this herb, there are solutions.
Make some more
The easiest way to tackle the problem is to make more of the dish without any basil in it. If you are making a tomato-based pasta sauce, simply throw together some more of the non-basil ingredients and add them to your present dish. This solution will double the amount of food that you are making, but should also dilute the basil flavor to tolerable levels. Even if you wind up with extra food, it should keep you from having to throw out your original dish.
If you have gone far overboard and do not have enough ingredients to make a whole new dish, you may still be able to correct your mistake. You can throw out some of what you have made and add the non-basil ingredients to what is left. This allows you to dilute it without spending a fortune on the dish.
Physically remove the basil
If the herb still sitting on the surface because you have not stirred it in yet, you might still be able to save the dish. Simply use a spoon or ladle to skim what you can off the surface. Note that this method is effective only if you catch your mistake soon after adding the basil. If you hesitate, all of the essential oils in the basil will be released into your dish and removing it will make no difference.
Add a fresh bell pepper
Slice a fresh bell pepper and add it to the sauce. The flavor of the pepper can offset excess basil. Note that this method will be effective in cases where you used a little bit too much basil. If you added far more than the recommended amount, a bell pepper may not be enough.
A dash or two of cayenne pepper powder may distract from too much basil in your dish. Note that people differ when it comes to tolerance to spicy foods, so you should proceed with caution when implementing this solution. Start with a little cayenne and increase to taste.
Parmesan cheese is an appropriate addition to many dishes that require basil and can be an effective way to counteract too much of that herb. Other cheeses can work as well. Depending on the dish, pecorino Romano or even mozzarella can be just as effective.
Add more garlic
Sometimes when you are dealing with a strong flavor, what you need is another strong flavor to cancel it out. Garlic has a way of balancing pungent herbal notes. It can also counter the bitter notes that excess basil can bring.
Cook it for longer
Fresh basil can handle moderate cooking times, but it will still fade if you cook it for long enough. If your dish can handle a few extra hours of cooking time, you may be able to cook out the extra basil flavor. This is more likely to work if you used fresh basil rather than the dried herb. The dried herb is more concentrated and therefore may continue to release its flavor for a long time.