How to add outline button with circular border and box shadow in Flutter?

Question

This is what I got.

OutlineButton(
          padding: EdgeInsets.all(5),
          shape: CircleBorder(),
          borderSide: BorderSide(
                 color: Colors.black,
                 style: BorderStyle.solid,
                 width: 2,
          ),
          onPressed: () => print("to be implemented"),
          child: Icon(Icons.settings),
 ),

How do I go about adding box shadow around these circular borders. I tried putting container inside the outline button and the icon within the container. But then the circular border is messed up if I apply padding.

I tried putting the outline button inside a container. But then the shadows are all over. Container does not glue to the circular shape of the outline button but takes its own shape and applies box shadow.