diff --git a/core/boot.js b/core/boot.js
index 8effee0930..488c5fa355 100644
--- a/core/boot.js
+++ b/core/boot.js
@@ -131,18 +131,6 @@ async function initFrontend() {
 async function initExpressApps() {
     debug('Begin: initExpressApps');
     const parentApp = require('./server/web/parent/app')();
-    const vhost = require('@tryghost/vhost-middleware');
-
-    // Mount the express apps on the parentApp
-
-    // ADMIN + API
-    const backendApp = require('./server/web/parent/backend')();
-    parentApp.use(vhost(backendApp.get('vhostArg'), backendApp));
-
-    // SITE + MEMBERS
-    const frontendApp = require('./server/web/parent/frontend')({});
-    parentApp.use(vhost(frontendApp.get('vhostArg'), frontendApp));
-
     debug('End: initExpressApps');
     return parentApp;
 }
diff --git a/core/server/web/parent/app.js b/core/server/web/parent/app.js
index 2b6780f464..6c5b226277 100644
--- a/core/server/web/parent/app.js
+++ b/core/server/web/parent/app.js
@@ -3,8 +3,10 @@ const config = require('../../../shared/config');
 const express = require('../../../shared/express');
 const compress = require('compression');
 const mw = require('./middleware');
+const vhost = require('@tryghost/vhost-middleware');
+const vhostUtils = require('./vhost-utils');
 
-module.exports = function setupParentApp() {
+module.exports = function setupParentApp(options = {}) {
     debug('ParentApp setup start');
     const parentApp = express('parent');
 
@@ -23,9 +25,17 @@ module.exports = function setupParentApp() {
     // @TODO: figure out if this is really needed everywhere? Is it not frontend only...
     parentApp.use(mw.ghostLocals);
 
+    // Mount the express apps on the parentApp
+
+    // ADMIN + API
+    const backendApp = require('./backend')();
+    parentApp.use(vhost(vhostUtils.getBackendHostArg(), backendApp));
+
+    // SITE + MEMBERS
+    const frontendApp = require('./frontend')(options);
+    parentApp.use(vhost(vhostUtils.getFrontendHostArg(), frontendApp));
+
     debug('ParentApp setup end');
 
     return parentApp;
 };
-
-// const vhostUtils = require('./vhost-utils');
diff --git a/core/server/web/parent/backend.js b/core/server/web/parent/backend.js
index 64ab05e05c..2e40dae378 100644
--- a/core/server/web/parent/backend.js
+++ b/core/server/web/parent/backend.js
@@ -1,6 +1,5 @@
 const debug = require('@tryghost/debug')('web:backend');
 const express = require('../../../shared/express');
-const vhostUtils = require('./vhost-utils');
 
 /**
  *
@@ -11,9 +10,6 @@ module.exports = () => {
     // BACKEND
     // Wrap the admin and API apps into a single express app for use with vhost
     const backendApp = express('backend');
-
-    backendApp.set('vhostArg', vhostUtils.getBackendHostArg());
-
     backendApp.use('/ghost/api', require('../api')());
     backendApp.use('/ghost/oauth', require('../oauth')());
     backendApp.use('/ghost/.well-known', require('../well-known')());
diff --git a/core/server/web/parent/frontend.js b/core/server/web/parent/frontend.js
index cea8c5e265..6276195eef 100644
--- a/core/server/web/parent/frontend.js
+++ b/core/server/web/parent/frontend.js
@@ -1,6 +1,5 @@
 const debug = require('@tryghost/debug')('frontend');
 const express = require('../../../shared/express');
-const vhostUtils = require('./vhost-utils');
 
 const shared = require('../shared');
 
@@ -15,8 +14,6 @@ module.exports = (options) => {
     // FRONTEND
     const frontendApp = express('frontend');
 
-    frontendApp.set('vhostArg', vhostUtils.getFrontendHostArg());
-
     // Force SSL if blog url is set to https. The redirects handling must happen before asset and page routing,
     // otherwise we serve assets/pages with http. This can cause mixed content warnings in the admin client.
     frontendApp.use(shared.middlewares.urlRedirects.frontendSSLRedirect);