diff --git a/xblock/runtime.py b/xblock/runtime.py
index <HASH>..<HASH> 100644
--- a/xblock/runtime.py
+++ b/xblock/runtime.py
@@ -460,7 +460,7 @@ class Mixologist(object):
             self._generated_classes[cls] = type(
                 cls.__name__ + 'WithMixins',
                 (cls, ) + self._mixins,
-                {'mixed_class': True}
+                {'unmixed_class': cls}
             )
 
         return self._generated_classes[cls]
diff --git a/xblock/test/test_runtime.py b/xblock/test/test_runtime.py
index <HASH>..<HASH> 100644
--- a/xblock/test/test_runtime.py
+++ b/xblock/test/test_runtime.py
@@ -413,3 +413,6 @@ class TestMixologist(object):
     # Test that mixins are applied in order
     def test_mixin_order(self):
         assert_is(1, self.mixologist.mix(FieldTester).number)
+
+    def test_unmixed_class(self):
+        assert_is(FieldTester, self.mixologist.mix(FieldTester).unmixed_class)
Add the unmixed class as an attribute to automixed classes