diff --git a/docs/Formula-Cookbook.md b/docs/Formula-Cookbook.md
index a59ab27fb0..438b481e28 100644
--- a/docs/Formula-Cookbook.md
+++ b/docs/Formula-Cookbook.md
@@ -757,6 +757,8 @@ Firstly, the overall environment in which Homebrew runs is filtered to avoid env
 
 The second level of filtering removes sensitive environment variables (such as credentials like keys, passwords or tokens) to avoid malicious subprocesses obtaining them (<https://github.com/Homebrew/brew/pull/2524>). This has the effect of preventing any such variables from reaching a formula's Ruby code as they are filtered before it is called. The specific implementation can be seen in the [`ENV.clear_sensitive_environment!` method](https://github.com/Homebrew/brew/blob/HEAD/Library/Homebrew/extend/ENV.rb).
 
+You can set environment variables in a formula's `install` method using `ENV["VARIABLE_NAME"] = "VALUE"`. An example can be seen in [the `gh` formula](https://github.com/Homebrew/homebrew-core/blob/fd9ad29f8e3ca9476f838ebb13794ddb7dafba00/Formula/gh.rb#L22).
+
 In summary, environment variables used by a formula need to conform to these filtering rules in order to be available.
 
 ## Updating formulae