diff --git a/docs/extensions/listings/custom-formats.yml b/docs/extensions/listings/custom-formats.yml
index 00c6f5a238..56a2e52af1 100644
--- a/docs/extensions/listings/custom-formats.yml
+++ b/docs/extensions/listings/custom-formats.yml
@@ -68,6 +68,12 @@
   description: >
     Quarto extension to generate a PDF with (pretty) LaTeX styling.
 
+- name: quarto-letter
+  path: https://github.com/produnis/quarto-letter
+  author: '[Jörg große Schlarmann](https://github.com/produnis)'
+  description: >
+    A Quarto extension for generating PDF letters using Typst or LaTeX
+
 - name: quarto-live
   path: https://github.com/r-wasm/quarto-live
   author: '[George Stagg](https://github.com/georgestagg)'