Well, if the aroma is truly in the food then there's not much you can do.
However, you can take steps to make sure that the aroma is subdued as much as possible.
It's quite possible that a large portion of the burnt aroma is merely in the air.
Turn exhaust fans on to get the aroma out of your kitchen asap Submerge the burnt surface in water as soon as possible to prevent the aroma from spreading
Be very careful "separating" the unburnt from the burnt Inhale something very strongly scented.
Why?
It's quite likely that a significant portion of the burnt smell is merely stuck in your nose.
If you can somehow nullify that source of the burning aroma, you can perhaps more accurately gauge if the food itself actually has it.
Possibly you could overpower it by adding something very fragrant to your dish that fits.
If your dish would work with lemon or lime this could help.
If it's a desert maybe cinnamon or cloves might be useful.
The best thing though is prevention.
Use lower heat when possible if you find yourself being regularly careless.
Using a better pot/pan may help also depending on what you are currently using.
Also, don't turn down help if your guests offer.
Make them stir!
:D
P.S. Don't inhale something dangerous like bleach or ammonia.
cooking.stackexchange.com/users/60/hobodave
It really depends on what you're cooking.
Something firm, like meat or bread, you can probably just cut off the burned part.
Anything with a liquid component, the burnt flavor is probably infused throughout.
Others may have better suggestions on how to mask the flavor, but again this will depend on exactly what it is.
cooking.stackexchange.com/users/106/GalacticCowboy
If the bottom of the soup or sauce starts to burn: Move pan away from heat.
Try to quickly move the upper parts into another pan by gently ladling off the top.
Don't stir and don't scrape the bottom.
This will minimize the burnt flavor in the food (which is what matters most).
If this happens regularly, try cooking with lower heat, and setting a timer to remind yourself to stir.
cooking.stackexchange.com/users/649/Tim Gilbert
Some home remedies: Apparently, for burnt rice, you can take the (papery) peels of onions to absorb burn aroma.
Some people use peanut butter in burnt (wettish) dishes.
Coffee flavor (if appropriate to the dish) can mask flavor
cooking.stackexchange.com/users/8457/Tobias Op Den Brouw
If you burn rice while steaming it - a slice of soft white bread placed on top in the pan really helps.
For sauces, if you know you burned it before stirring it, carefully spoon the top layer into a new pan.
At least that way you won't be mixing in burnt chunks throughout the dish.
One more thing, try using heavier bottom pans as they will tend not to burn as much.
You might also try a heat spreader which is a little thing you can buy that sits between your burner and the base of the pan.
These work great for anything that is supposed to cook slowly for a long time.
cooking.stackexchange.com/users/335/octonion
I sometimes burn the bottom of the pan due to carelessness or not stirring enough. The burnt smell tends to persist even after I seperate out the un-burnt bits. Is there any way to fix this?
How do I get the burnt aroma off burnt food?
cooking.stackexchange.com
<smell>
cooking.stackexchange.com/questions/1032
cooking.stackexchange.com/users/13/Sonia Balagopalan
You may be able to cut off the burnt part with firmer foods like meat or bread, but with liquids the taste may have spread throughout the dish. Some strong flavours can mask this or foods like bread or onion peel can absorb some of the taste. Don't stir or scrape the bottom, and try to get the smell out of the kitchen with an extractor fan. There is not much you can do to remove a burnt taste once it has permeated the food. If you see that it has burnt onto the bottom of the pan, don't scrape to avoid the burnt bits mixing with the rest.
There is not much you can do if the burnt aroma has infused into the food. It might just be the smell that is making you think it tastes burnt.  With meat products, you can just cut the burnt bit off. With anything else, try adding spices to mask the burnt taste. Try peanut butter in wet dishes, onion peels or white bread for rice. If you see the pan has burnt, don't stir or scrape so the burnt bits don't mix into your food.