diff --git a/stac_fastapi/core/stac_fastapi/core/core.py b/stac_fastapi/core/stac_fastapi/core/core.py
index 56afcbc8..dd9c9897 100644
--- a/stac_fastapi/core/stac_fastapi/core/core.py
+++ b/stac_fastapi/core/stac_fastapi/core/core.py
@@ -377,7 +377,7 @@ async def get_item(
 
     @staticmethod
     def _return_date(
-        interval: Optional[Union[DateTimeType, str]]
+        interval: Optional[Union[DateTimeType, str]],
     ) -> Dict[str, Optional[str]]:
         """
         Convert a date interval.
@@ -724,15 +724,14 @@ async def update_item(
 
         """
         item = item.model_dump(mode="json")
-        base_url = str(kwargs["request"].base_url)
         now = datetime_type.now(timezone.utc).isoformat().replace("+00:00", "Z")
         item["properties"]["updated"] = now
 
         await self.database.check_collection_exists(collection_id)
         await self.delete_item(item_id=item_id, collection_id=collection_id)
-        await self.create_item(collection_id=collection_id, item=Item(**item), **kwargs)
-
-        return ItemSerializer.db_to_stac(item, base_url)
+        return await self.create_item(
+            collection_id=collection_id, item=Item(**item), **kwargs
+        )
 
     @overrides
     async def delete_item(
diff --git a/stac_fastapi/core/stac_fastapi/core/serializers.py b/stac_fastapi/core/stac_fastapi/core/serializers.py
index 9b0d36d4..22546703 100644
--- a/stac_fastapi/core/stac_fastapi/core/serializers.py
+++ b/stac_fastapi/core/stac_fastapi/core/serializers.py
@@ -1,4 +1,5 @@
 """Serializers."""
+
 import abc
 from copy import deepcopy
 from typing import Any, List, Optional
@@ -65,6 +66,10 @@ def stac_to_db(cls, stac_data: stac_types.Item, base_url: str) -> stac_types.Ite
         item_links = resolve_links(stac_data.get("links", []), base_url)
         stac_data["links"] = item_links
 
+        stac_data["assets"] = [
+            {"es_key": k, **v} for k, v in stac_data.get("assets", {}).items()
+        ]
+
         now = now_to_rfc3339_str()
         if "created" not in stac_data["properties"]:
             stac_data["properties"]["created"] = now
@@ -102,7 +107,7 @@ def db_to_stac(cls, item: dict, base_url: str) -> stac_types.Item:
             bbox=item.get("bbox", []),
             properties=item.get("properties", {}),
             links=item_links,
-            assets=item.get("assets", {}),
+            assets={a.pop("es_key"): a for a in item.get("assets", [])},
         )
 
 
@@ -127,6 +132,9 @@ def stac_to_db(
         collection["links"] = resolve_links(
             collection.get("links", []), str(request.base_url)
         )
+        collection["assets"] = [
+            {"es_key": k, **v} for k, v in collection.get("assets", {}).items()
+        ]
         return collection
 
     @classmethod
@@ -173,5 +181,9 @@ def db_to_stac(
             collection_links += resolve_links(original_links, str(request.base_url))
         collection["links"] = collection_links
 
+        collection["assets"] = {
+            a.pop("es_key"): a for a in collection.get("assets", [])
+        }
+
         # Return the stac_types.Collection object
         return stac_types.Collection(**collection)