Heat the half-and-half, pumpkin, brown sugar
, salt, cinnamon, and nutmeg in a heat-proof bowl set over a pan of simmering water until hot, about 5 minutes. Whisk the egg yolks in another bowl, stir some of the hot pumpkin into the egg yolks to heat them, then pour the egg-pumpkin mixture back into the double boiler
and stir well. Heat the mixture over the simmering water for another 4 to 5 minutes, until it begins to thicken, stirring constantly. You don't want the eggs
to scramble. Remove from the heat.
Dissolve the gelatin in 1/2 cup cold water. Add the dissolved gelatin
, banana, and orange zest to the pumpkin mixture and mix well. Set aside to cool.