//Add new property to claims on login

private async Task SignInAsync(User user, ClaimsIdentity identity = null, bool rememberMe = false)
{
    if (identity == null)
    {
        identity = await _userManager.CreateIdentityAsync(user, DefaultAuthenticationTypes.ApplicationCookie);
    }

    identity.AddClaim(new Claim("Application_UserEmail", user.EmailAddress)); //SETTING NEW PROPERTY

    AuthenticationManager.SignOut(DefaultAuthenticationTypes.ApplicationCookie);
    AuthenticationManager.SignIn(new AuthenticationProperties { IsPersistent = rememberMe }, identity);
}