diff --git a/core/lib/Drupal/Core/Entity/EntityTypeManager.php b/core/lib/Drupal/Core/Entity/EntityTypeManager.php
index 399963f..6dbe4d2 100644
--- a/core/lib/Drupal/Core/Entity/EntityTypeManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityTypeManager.php
@@ -87,7 +87,7 @@ public function processDefinition(&$definition, $plugin_id) {
     // Add the UUID link template if applicable.
     $route_providers = $definition->getRouteProviderClasses();
     $has_uuid_route = isset($route_providers['html']) && in_array(EntityUuidRouteProviderInterface::class, class_implements($route_providers['html']), TRUE);
-    if ($definition->hasKey('uuid') && $definition->hasViewBuilderClass() && $has_uuid_route) {
+    if (!$definition->hasLinkTemplate('uuid') && $definition->hasKey('uuid') && $definition->hasViewBuilderClass() && $has_uuid_route) {
       $definition->setLinkTemplate('uuid', "/{$plugin_id}/{{$plugin_id}}");
     }
     // All link templates must have a leading slash.
diff --git a/core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php b/core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php
index c20df77..857d0f1 100644
--- a/core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php
+++ b/core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php
@@ -153,13 +153,12 @@ public function checkNodeAccess(array $tree) {
         $query->condition('status', NODE_PUBLISHED);
       }
 
-      $nids = $query->execute();
-      if ($nids) {
-        foreach ($nids as $nid) {
-          if (isset($node_links[$nid])) {
-            foreach ($node_links[$nid] as $key => $link) {
-              $node_links[$nid][$key]->access = $access_result;
-            }
+      // Cast to an array so we can loop, even if there are no results.
+      $nids = (array) $query->execute();
+      foreach ($nids as $nid) {
+        if (isset($node_links[$nid])) {
+          foreach ($node_links[$nid] as $key => $link) {
+            $node_links[$nid][$key]->access = $access_result;
           }
         }
       }
diff --git a/core/lib/Drupal/Core/ParamConverter/EntityConverter.php b/core/lib/Drupal/Core/ParamConverter/EntityConverter.php
index 0d93051..855356b7 100644
--- a/core/lib/Drupal/Core/ParamConverter/EntityConverter.php
+++ b/core/lib/Drupal/Core/ParamConverter/EntityConverter.php
@@ -58,6 +58,8 @@ public function __construct(EntityManagerInterface $entity_manager) {
 
   /**
    * {@inheritdoc}
+   *
+   * The value here can be either a serial entity ID, or the entity UUID.
    */
   public function convert($value, $definition, $name, array $defaults) {
     $entity_type_id = $this->getEntityTypeFromDefaults($definition, $name, $defaults);
diff --git a/core/modules/menu_ui/menu_ui.module b/core/modules/menu_ui/menu_ui.module
index cab395f..fdf1f7d 100644
--- a/core/modules/menu_ui/menu_ui.module
+++ b/core/modules/menu_ui/menu_ui.module
@@ -204,6 +204,7 @@ function menu_ui_get_menu_link_defaults(NodeInterface $node) {
       $query = \Drupal::entityQuery('menu_link_content');
       $group = $query->orConditionGroup()
         ->condition('link.uri', 'entity:node/' . $node->id())
+        ->condition('link.uri', 'entity:node/' . $node->uuid())
         ->condition('link.uri', 'internal:/node/' . $node->id())
         ->condition('link.uri', 'internal:/node/' . $node->uuid());
       $query->condition($group)
@@ -219,6 +220,7 @@ function menu_ui_get_menu_link_defaults(NodeInterface $node) {
       $query = \Drupal::entityQuery('menu_link_content');
       $group = $query->orConditionGroup()
         ->condition('link.uri', 'entity:node/' . $node->id())
+        ->condition('link.uri', 'entity:node/' . $node->uuid())
         ->condition('link.uri', 'internal:/node/' . $node->id())
         ->condition('link.uri', 'internal:/node/' . $node->uuid());
       $query->condition($group)
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php
index 6c96e79..6d9796c 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php
@@ -17,6 +17,7 @@
 use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\Core\Entity\EntityTypeManager;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Entity\Routing\DefaultHtmlRouteProvider;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\StringTranslation\TranslationInterface;
 use Drupal\Tests\UnitTestCase;
@@ -99,12 +100,12 @@ protected function setUpEntityTypeDefinitions($definitions = []) {
       // Give the entity type a legitimate class to return.
       $entity_type->getClass()->willReturn($class);
 
-      // Don't allow uuid key.
-      $entity_type->hasKey('uuid')->willReturn(FALSE);
-
       // Or route provider.
       if (!$entity_type->getMethodProphecies('getRouteProviderClasses')) {
         $entity_type->getRouteProviderClasses()->willReturn([]);
+        // Don't allow uuid key.
+        $entity_type->hasKey('uuid')->willReturn(FALSE);
+        $entity_type->hasLinkTemplate('uuid')->willReturn(FALSE);
       }
 
       $definitions[$key] = $entity_type->reveal();
@@ -308,6 +309,10 @@ public function testGetRouteProviders() {
     $apple = $this->prophesize(EntityTypeInterface::class);
     $apple->getRouteProviderClasses()->willReturn(['default' => TestRouteProvider::class]);
 
+    // Don't allow uuid key.
+    $apple->hasKey('uuid')->willReturn(FALSE);
+    $apple->hasLinkTemplate('uuid')->willReturn(FALSE);
+
     $this->setUpEntityTypeDefinitions([
       'apple' => $apple,
     ]);
@@ -319,6 +324,27 @@ public function testGetRouteProviders() {
   }
 
   /**
+   * @covers ::processDefinition
+   */
+  public function testUuidRouteProviders() {
+    $apple = $this->prophesize(EntityTypeInterface::class);
+    $apple->getRouteProviderClasses()->willReturn(['html' => DefaultHtmlRouteProvider::class]);
+
+    // Allow uuid key.
+    $apple->hasKey('uuid')->willReturn(TRUE);
+    $apple->hasLinkTemplate('uuid')->willReturn(FALSE);
+    $apple->hasViewBuilderClass()->willReturn(TRUE);
+
+    $this->setUpEntityTypeDefinitions([
+      'apple' => $apple,
+    ]);
+
+    $apple->setLinkTemplate('uuid', '/apple/{apple}')->shouldBeCalled();
+    $definition = $apple->reveal();
+    $this->entityTypeManager->processDefinition($definition, 'apple');
+  }
+
+  /**
    * Tests the processDefinition() method.
    *
    * @covers ::processDefinition