Drawing a rectangle using OnGUI()

I'm trying to draw a rectangle with a clear fill, but im having some issues. I've managed to draw a filled rectangle with the following code

 Texture2D rectTexture = null;
     GUIStyle rectStyle = null;
     
     //Note that this function is only meant to be called from OnGUI() functions.
     void GUIDrawRect(Rect position, Color color) 
     {
         if(rectTexture == null)
             rectTexture = new Texture2D(1, 1);
         
         if(rectStyle == null)
             rectStyle = new GUIStyle();    
 
         rectTexture.SetPixel(0, 0, color);
         rectTexture.Apply();
         rectStyle.normal.background = rectTexture;
     
         GUI.Box(position, GUIContent.none, rectStyle);
     }

But I really need the middle of the rectangle not filled. I tried drawing a 2nd rectangle of Color.clear, but that didn't work (I didn't expect it to). If anyone has any insight on this that would be great.