diff --git a/mu-plugins/_core-wp-cron-logger.php b/mu-plugins/_core-wp-cron-logger.php
new file mode 100644
index 0000000..510640f
--- /dev/null
+++ b/mu-plugins/_core-wp-cron-logger.php
@@ -0,0 +1,39 @@
+<?php
+
+/*
+ * Plugin Name: Log WP-Cron (HTTP) callback output and errors
+ * Plugin URI: https://github.com/szepeviktor/wordpress-website-lifecycle
+ */
+
+add_filter(
+    'cron_request',
+    static function ($cron_request_array) {
+        add_action(
+            'http_api_debug',
+            static function ($response) {
+                static $run_once = 0;
+                $run_once += 1;
+                if ($run_once !== 1) {
+                    return;
+                }
+                if (is_wp_error($response)) {
+                    error_log(sprintf(
+                        'WP-Cron error: (%s) "%s"',
+                        $response->get_error_code(),
+                        $response->get_error_message()
+                    ));
+                    return;
+                }
+                if ($response['body'] === '') {
+                    return;
+                }
+                error_log(sprintf('WP-Cron output: "%s"', $response['body']));
+            },
+            10,
+            1
+        );
+        return $cron_request_array;
+    },
+    10,
+    1
+);