  We calculate the baryon asymmetry generated at the electroweak phase
transition in the minimal supersymmetric standard model, using a new method to
compute the CP-violating asymmetry in the Higgsino flux reflected into the
unbroken phase. The method is based on a Higgs insertion expansion. We find
that the CP asymmetry at leading order is proportional to the change in $\tan
\beta$ in the bubble wall, which is at most of order $10^{-2}$, while at
next-to-leading order this suppression factor disappears. This result may
enhance the final baryon asymmetry generated during the electroweak phase
transition for small $\Delta \beta (< 10^{-3}$).
