I like mayonnaise fine, but the improvement I came to suggest is creamy horseradish. Yum!
I’m onboard with that! 
Obviously the tomato needs to be quality, or the whole exercise is going to be disappointing. However, there is one key that you all are missing: The tomato must be touching the mayonnaise.
Hold on, stick with me here. I’m not just being childish. There is honestly something magical that happens when tomato juice mixes with mayo that creates a new distinct flavor that is greater than the sum of its parts, and you don’t get that mixing if you put the bacon or the lettuce against the mayo.
This applies to tomato-cucumber sandwiches, or any sandwich with tomatoes.
This is correct. It’s a BLT. The bacon comes first, then the lettuce, then the tomato. The only time the tomato doesn’t touch the mayonnaise is when you make a BLAT. In that case, the avocado touches the mayo.
Tangent: If you’re making a sandwich with meat and mustard, the meat touches the mustard and the lettuce/tomato/cheese/whatever touches the mayo.
No, this is definitely wrong. You’ve missed the point.
Avocado+Mayo=Avocado+Mayo
Tomato+Mayo=^^AMAZING^^
If you want your avocado touching mayo, you need to mayo both slices and put the avocado on one side, and the tomato on the other. The tomato MUST touch the mayo, and yes, it actually affects the final flavor.
I’ve recently been enjoying the BLT taco. You have to use slightly different slicing on your tomato, but the tortilla (corn!) really complements the other flavors. It’s genius. Of course all quality ingredients, especially good quality corn tortillas, lightly grilled and warm.
I put mayo on the bottom toast, then layer tomatoes, then bacon, then lettuce on top, then a tiny bit of mayo on the top toast.
That’s why, during the peak of tomato season, a tomato sandwich is soooo good.
Of course. Lose the lettuce. It has hardly any flavor or food value.
The lettuce offers the necessary non-savory crunch factor. Now granted, the lettuce needs to be proportional to the rest of the sandwich. Too much is silly. But it needs to be there.
Avocado doesn’t. Ever.
Definitely this, since it allows you to cover the bottom toast with tomato better than putting bacon first. And yes on lettuce for the crunch.
Yes! Flatbreads are also an equivalent substitute for toast imo.
Yep. Like I said in the last sentence of my reply, A BLT is primarily a tomato sandwich. That’s the star of the show. Also note the pull quote on that webpage: “A BLT is a tomato sandwich, seasoned with bacon.” That’s why I don’t make them until tomato season. There’s just no point to having a BLT if you don’t have good garden tomatoes. I never order this sandwich in diners as the tomatoes there invariably suck.
I’m slightly (but only slightly I guess, no accounting for taste as they say) surprised that everyone doesn’t already do this. Dry un-condimented toast is a sad, sad thing - the lubrication is necessary and extra fat is generally welcome 
.
I do tend to lose the lettuce 90% of the time, replaced with avocado maybe 20% of the time.
Avocado over mayo, for sure. or guac, which is really just mashed avocado with some spices (so you can spread it like mayo). Then you have all the elements and the B still featured as the only protein, which should appease the purists. I’m OK with the BELT, but people adding a chicken breast or burger or something no longer have a BLT, now you have a grilled chicken club sandwich or bacon cheeseburger or whatever.
Yes, of course on a sandwich with mustard, the mustard is against the meat. But much though I love mustard, it doesn’t belong on a BLT, and hence is a digression for this thread.
And while there are plenty of sandwiches that include bacon, lettuce, tomato, and other toppings, and many of them are even good sandwiches, in most cases adding other ingredients leaves you with some other sort of sandwich, not a BLT.
Oh yeah, it can be improved. For some reason it ususlly (IME) has mayo on it. Leave that off of it, and voila, improved. Also, the tomatoes. Go ahead and leave those off, too- another improvement. I guess that would change the name of the sandwich, though. But certainly throw the jar of mayo out into the street and let cars run it over!
My BLT is fairly simple:
Bacon, lettuce, tomato, mayo, lightly-toasted white or wheat bread. My wist is to toss on a few banana pepper rings, or splash some red wine vinegar as a quick substitute. That little bit of tartness helps to make up for lackluster tomatoes when they’re out of season. During winter months I’ll use Campari tomatoes because they have a bit more of an acid kick.
Avocado improves everything. The BLTA is pretty common here in So. Cal.
It occurred to me, eating a fast food burger with too much mayo, a tomato, and onion that adding said onion really helped make up for the lack of flavor in the store-bought tomato.
So that’s my answer. If the tomato you get isn’t flavorful enough, add a bit of onion. Not a BLAT, but a BLOT.