diff --git a/falcon/response.py b/falcon/response.py
index 7cdbc71..6c8223c 100644
--- a/falcon/response.py
+++ b/falcon/response.py
@@ -251,9 +251,24 @@ class Response(object):
             self._cookies[name]["httponly"] = http_only
 
     def unset_cookie(self, name):
-        """Unset a cookie in the response."""
-        if self._cookies is not None and name in self._cookies:
-            del self._cookies[name]
+        """Unset a cookie in the response
+
+        Note:
+            This will clear the contents of the cookie, and instruct
+            the browser to immediately expire its own copy of the
+            cookie, if any.
+        """
+        if self._cookies is None:
+            self._cookies = SimpleCookie()
+
+        self._cookies[name] = ""
+
+        # NOTE(Freezerburn): SimpleCookie apparently special cases the
+        # expires attribute to automatically use strftime and set the
+        # time as a delta from the current time. We use -1 here to
+        # basically tell the browser to immediately expire the cookie,
+        # thus removing it from future request objects.
+        self._cookies[name]["expires"] = -1
 
     def get_header(self, name):
         """Retrieve the raw string value for the given header.
diff --git a/falcon/util/misc.py b/falcon/util/misc.py
index 00db982..7c39661 100644
--- a/falcon/util/misc.py
+++ b/falcon/util/misc.py
@@ -128,6 +128,7 @@ def http_date_to_dt(http_date, obs_date=False):
 
     time_formats = (
         '%a, %d %b %Y %H:%M:%S %Z',
+        '%a, %d-%b-%Y %H:%M:%S %Z',
         '%A, %d-%b-%y %H:%M:%S %Z',
         '%a %b %d %H:%M:%S %Y',
     )
diff --git a/tests/test_cookies.py b/tests/test_cookies.py
index fe0fa8c..07408c2 100644
--- a/tests/test_cookies.py
+++ b/tests/test_cookies.py
@@ -1,11 +1,13 @@
+import re
 import sys
-import falcon
-import falcon.testing as testing
-
-from falcon.util import TimezoneGMT
 from datetime import datetime, timedelta, tzinfo
 
 from six.moves.http_cookies import Morsel
+from testtools.matchers import LessThan
+
+import falcon
+import falcon.testing as testing
+from falcon.util import TimezoneGMT, http_date_to_dt
 
 
 class TimezoneGMTPlus1(tzinfo):
@@ -109,12 +111,23 @@ class TestCookies(testing.TestBase):
     def test_response_unset_cookie(self):
         resp = falcon.Response()
         resp.unset_cookie("bad")
-        resp.set_cookie("bad", "cookie", max_age=301)
+        resp.set_cookie("bad", "cookie", max_age=300)
         resp.unset_cookie("bad")
 
         morsels = list(resp._cookies.values())
+        self.assertEqual(len(morsels), 1)
 
-        self.assertEqual(len(morsels), 0)
+        bad_cookie = morsels[0]
+        self.assertEqual(bad_cookie['expires'], -1)
+
+        output = bad_cookie.OutputString()
+        self.assertTrue('bad=;' in output or 'bad="";' in output)
+
+        match = re.search('expires=([^;]+)', output)
+        self.assertIsNotNone(match)
+
+        expiration = http_date_to_dt(match.group(1), obs_date=True)
+        self.assertThat(expiration, LessThan(datetime.utcnow()))
 
     def test_cookie_timezone(self):
         tz = TimezoneGMT()
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 5507361..b082c38 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -79,6 +79,15 @@ class TestFalconUtils(testtools.TestCase):
             falcon.http_date_to_dt('Thu, 04 Apr 2013 10:28:54 GMT'),
             datetime(2013, 4, 4, 10, 28, 54))
 
+        self.assertRaises(
+            ValueError,
+            falcon.http_date_to_dt, 'Thu, 04-Apr-2013 10:28:54 GMT')
+
+        self.assertEqual(
+            falcon.http_date_to_dt('Thu, 04-Apr-2013 10:28:54 GMT',
+                                   obs_date=True),
+            datetime(2013, 4, 4, 10, 28, 54))
+
         self.assertRaises(
             ValueError,
             falcon.http_date_to_dt, 'Sun Nov  6 08:49:37 1994')