Bread

Bread is humanity's first food-related invention. It turned blah-tasting seeds into a delicious foodstuff that lasted for a reasonable time before spoiling, was easy to handle and eat (unlike seeds, where you can easily end up dropping large portions of it if you're not careful), and more importantly, could also hold OTHER foods so you would never be bored eating it. (Stuff something into your bread. A filling? A dip?)
What could we do to improve bread? Quite possibly, a number of things.
Vitamin enrichment is a good start. A lot of bread is made of white flour, and much of the nutrition is lost in the refinement. So most of this has an "enrichment" process to put some back. This is why, when you read the ingridents list on your loaf of bread, it says "enriched white flour." Health food fans note that the enrichment is someone less than what was taken out, famously one compared it to being robbed of $25 and being refunded $0.99. So...deeper enriched bread.
Longer lasting bread has been invented hundreds of years ago in the form of hardtack, which I wrote about. Hardtack is typically crunchy, and most recipes of it don't taste very good. Mostly because that's the point: It's an emergency food for planning ahead for when no other food is available, and you eat it because no other food is available.
Also, a very hard bread has been invented by coal miners in New Zealand for not falling apart in the mine, and for being cheap enough that you can throw away the parts that inevitably get covered in coal dust.
I can imagine one improvement: Rapid baking bread. In less than five minutes of oven time, it goes from inedible batter to edible bread. I hope to get it down to less than two minutes, ultimately. The first means of accomplishing this will be a study of leavening agents, to determine the fastest acting one.
As a second idea, a hardtack vault. This would be an extremely large underground storage area, filled to the brim with hardtack. In the event of economic crisis, the vault would be opened, and hardtack passed around to the citizenry, ensuring their survival to better, more gourmet, times.