Where, by reason of exceptional narrowness, shallowness or shape of a specific piece of property, or by reason of exceptional topographic conditions or by reason of other extraordinary and exceptional situations or condition of such piece of property, the strict application of any regulation pursuant to Article V of this chapter would result in peculiar and exceptional practical difficulties to, or exceptional and undue hardship upon, the developer of such property, grant, upon an application or appeal relating to such property, a variance from such strict application of such regulation so as to relieve such difficulties or hardships, including a variance for a conditional use; provided, however, that no variance shall be granted under this subsection to allow a structure or use in a district restricted against such structure or use.