diff --git a/lib/middleware/runner.rb b/lib/middleware/runner.rb
index 802b76e..d37c1f4 100644
--- a/lib/middleware/runner.rb
+++ b/lib/middleware/runner.rb
@@ -4,7 +4,7 @@ module Middleware
   # in order, then reversing the order.
   class Runner
     # A middleware which does nothing
-    EMPTY_MIDDLEWARE = lambda { |env| }
+    EMPTY_MIDDLEWARE = lambda { |env| env }
 
     # Build a new middleware runner with the given middleware
     # stack.