single purpose will

What is the name of your state (only U.S. law)? Illinois

Can an individual, who chooses to have no other will, construct
a will to leave only a single item (real estate property) to another?

There can be only one valid will - usually the last one written that meets the requirements of state law as a valid will.

Sure, you can write a will that specifically devises only a single asset. Any other assets that you own at death would be distributed according to the will's residuary clause, if such a clause is included in the will. If there isn't such a clause, any other assets would be distributed as if you had died intestate (without a will).