I'm having issues trying to get NSubstitute to return an IEnumerable interface from a Task.

The factory I'm mocking:

    public interface IWebApiFactory<T> : IDisposable
    {
        <T> GetOne(int id);
        Task<IEnumerable<T>> GetAll();
        Task<IEnumerable<T>> GetMany();
        void SetAuth(string token);
    }

The test method:

[TestMethod]
public async Task TestMutlipleUsersAsViewResult()
{
    var employees = new List<EmployeeDTO>()
    {
        new EmployeeDTO(),
        new EmployeeDTO()
    };

    // Arrange
    var factory = Substitute.For<IWebApiFactory<EmployeeDTO>>();
    factory.GetMany().Returns(Task.FromResult(employees));
}

The error I am getting is:

Error 8 Argument 2: cannot convert from 'System.Threading.Tasks.Task>' to 'System.Func>>'