The half dollars struck "in commemoration of the three hundredth anniversary of the founding of the Province of Maryland" were authorized on May 9, 1934. The law authorized 25,000 coins to be struck on behalf of the Maryland Tercentenary Commission.
The Mint struck all 25,000 coins in July 1934 and delivered them to the Commission; advertisements placed by the Commission at the time state that the coins were issued on July 10th.
In early 1935, the Maryland Tercentenary Commission sent a request to the Treasury Department/US Mint for 5,000 additional Maryland half dollars with a 1935 date; the Mint denied the request in February, stating "It is obvious that the issue of 5,000 pieces would create an artificial market and send the coins to a very high premium. It is felt that the Department, and, perhaps, your Commission would be open to criticism by those who have purchased the 1934 coins in good faith..."
The Mint also reminded the Commission that it had already struck all 25,000 of the half dollars authorized in 1934 and was therefore unable to strike additional coins for them.
Once the 1934 Tercentenary dates had passed, sales of the Commission's coins slowed. It appears that the Commission was hoping to
jump start coin sales by adding a scarcity to its mix of offerings (its commemorative medal was also still available, for example).
In order for the Commission to have secured 5,000 1935-dated coins, it would have had to sponsor a new bill that would have needed to be passed by Congress and signed by the President. Such a bill could have authorized a return of 5,000 1934-dated half dollars to the Mint for re-striking or authorized an additional 5,000 coins with a 1935 date. It appears, the Commission did not want to go in such a formal direction, however, as no bills/amendments were introduced in Congress on its behalf.
And so, collectors have a one-year type for the Maryland half dollar!
1934 Maryland Tercentenary Half Dollar

For other of my posts about commemorative coins and medals, including more on the history of the Maryland Tercentenary half dollar, see:
Commems Collection.*
Note: The quote in the thread title comes from the stone dining hall scene in the 1968 movie version of Charles Dickens' classic novel Oliver Twist
. A movie well worth watching if you haven't yet seen it (and don't have time to read the book).