diff --git a/core/src/__test__/htmlEncode.test.ts b/core/src/__test__/htmlEncode.test.ts
new file mode 100644
index 00000000..82071301
--- /dev/null
+++ b/core/src/__test__/htmlEncode.test.ts
@@ -0,0 +1,17 @@
+import rehypePrism from 'rehype-prism-plus';
+import type { PluggableList } from 'unified';
+import { htmlEncode, processHtml } from '../utils';
+
+it.each([
+  '```html\n<div title="x&y" />\n```',
+  '<div>&lt; & "quoted"</div>',
+  '```js\nif (a < b && b > 0) {}\n```',
+])('preserves preview text and escapes markup: %s', (value) => {
+  const configurations: PluggableList[] = [[], [[rehypePrism, { ignoreMissing: true }]]];
+  for (const plugins of configurations) {
+    const container = document.createElement('div');
+    container.innerHTML = processHtml(`<pre><code class="language-markdown">${htmlEncode(value)}</code></pre>`, plugins);
+    expect(container.querySelector('code')?.textContent).toBe(value);
+    expect(container.querySelector('code > div')).toBeNull();
+  }
+});
diff --git a/core/src/utils.ts b/core/src/utils.ts
index 0c9764ec..15c83520 100644
--- a/core/src/utils.ts
+++ b/core/src/utils.ts
@@ -11,12 +11,6 @@ export const processHtml = (html: string, plugins: PluggableList = [] as Pluggab
 
 export function htmlEncode(sHtml: string) {
   return sHtml
-    .replace(/```(tsx?|jsx?|html|xml)(.*)\s+([\s\S]*?)(\s.+)?```/g, (str: string) => {
-      return str.replace(
-        /[<&"]/g,
-        (c: string) => (({ '<': '&lt;', '>': '&gt;', '&': '&amp;', '"': '&quot;' }) as Record<string, string>)[c],
-      );
-    })
     .replace(
       /[<&"]/g,
       (c: string) => (({ '<': '&lt;', '>': '&gt;', '&': '&amp;', '"': '&quot;' }) as Record<string, string>)[c],