diff --git a/jupyter_server/utils.py b/jupyter_server/utils.py
index 5823321e7a..3a1ebd24d6 100644
--- a/jupyter_server/utils.py
+++ b/jupyter_server/utils.py
@@ -3,7 +3,6 @@
 # Distributed under the terms of the Modified BSD License.
 import errno
 import importlib.util
-import inspect
 import os
 import socket
 import sys
@@ -14,6 +13,7 @@
 from urllib.request import pathname2url  # noqa: F401
 
 from _frozen_importlib_external import _NamespacePath
+from jupyter_core.utils import ensure_async  # noqa: F401
 from packaging.version import Version
 from tornado.httpclient import AsyncHTTPClient, HTTPClient, HTTPRequest
 from tornado.netutil import Resolver
@@ -173,23 +173,6 @@ def _check_pid_posix(pid):
     check_pid = _check_pid_posix
 
 
-async def ensure_async(obj):
-    """Convert a non-awaitable object to a coroutine if needed,
-    and await it if it was not already awaited.
-    """
-    if inspect.isawaitable(obj):
-        try:
-            result = await obj
-        except RuntimeError as e:
-            if str(e) == "cannot reuse already awaited coroutine":
-                # obj is already the coroutine's result
-                return obj
-            raise
-        return result
-    # obj doesn't need to be awaited
-    return obj
-
-
 async def run_sync_in_loop(maybe_async):
     """**DEPRECATED**: Use ``ensure_async`` instead."""
     warnings.warn(
diff --git a/pyproject.toml b/pyproject.toml
index d350a106b3..93d2c6d2ce 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,7 +31,7 @@ dependencies = [
     "argon2-cffi",
     "jinja2",
     "jupyter_client>=7.4.4",
-    "jupyter_core>=4.9.2",
+    "jupyter_core>=4.12,!=~5.0",
     "jupyter_server_terminals",
     "nbconvert>=6.4.4",
     "nbformat>=5.3.0",