I'm assuming that you made the core out of iron, and wound it with insulated (enamelled) wire.
In which case, yes, it will work.
It won't be great, but it will work.
As you have only one lamination, its cross sectional area will be very small, so it will need very little VT constant to saturate it. (VT is voltage * time) So it will have to work at a low voltage and high frequency.
As your core is silicon-iron, it won't work very well at high frequency.
Your primary and secondary are on different parts of the structure, so the coupling between them won't be very good.
If you use a stack of laminations, arranged in a rectangle, then wind the two windings all on one side, one winding on top of the other, then it might be quite good.
If the enamelled wire is in direct contact with the metal laminations there is a risk that any movement will damage the enamel insulation and result in a short circuit.
OK, "will it work?" "Yes BUT" is the answer. The side with very little wire will deliver a very low voltage if it is used as the output (secondary winding)
As has been stated, it will not be very efficient, and that means it will possibly get rather hot.
What were you planning on using to supply the power to the transformer??