I will describe the calculation of one-loop amplitudes containing a Higgs boson coupled to gluons in the limit of a large top quark mass. Treating the Higgs as the real part of a complex field that couples to the self-dual field strengths. I will describe how we use four-dimensional unitarity to construct the cut-containing contributions and a hybrid of Feynman diagram and recursive based techniques to determine the rational pieces. I will present the missing helicity configuration which completes the analytic calculation of gg-$>$ Hgg.