Application.cfc

<cfcomponent>
    

    <cffunction name="onCFCRequest" access="public" returntype="any" output="false">
        <cfargument name="cfcname" type="string" />
        <cfargument name="method" type="string" />
        <cfargument name="args" type="struct" />

        <cfset var result = "" />
    
        <cfif structKeyExists(URL, "returnFormat") AND NOT listFindNoCase("json,wddx,plain,xml", URL.returnFormat)>
            <cfset structDelete(URL, "returnFormat") />
        </cfif> 
            
        <cfinvoke component="RemoteProxy" method="callMethod" argumentCollection="#arguments#" returnvariable="result" />
            
        <cfreturn result />
    </cffunction>

</cfcomponent>     

RemoteProxy.cfc

<cfcomponent>
    
    <cffunction name="callMethod" access="remote">
        <cfargument name="cfcname" type="string" />
        <cfargument name="method" type="string" />
        <cfargument name="args" type="struct" />

        <cfset var result = "" />
        
        <cfinvoke component="#arguments.cfcname#" method="#arguments.method#" argumentCollection="#arguments.args#" returnvariable="result" /> 
        
        <cfif structKeyExists(URL, "returnFormat") AND URL.returnFormat EQ "plain">
            <cfset result = result.toString() />
        </cfif>

        <cfreturn result />
    </cffunction>
</cfcomponent>