Preheat the oven to 350F/180C. Line a 13x9" Swiss roll pan with parchment paper, then set aside
In a medium bowl, mix together the flour, baking powder, ginger, cinnamon, nutmeg, and salt. Set aside.
Using a hand or stand mixer fitted with the whisk attachment, whisk the egg whites until soft peaks form. Add the sugar, and mix until firm peaks form. Set aside.
Using the whisk again, mix the egg yolks on high speed until thickened. Add the molasses, and honey, and mix well. Carefully fold the egg white mixture into the egg yolk mixture.
Gently fold the dry ingredients into the mixture until just combined.
Pour the batter into the prepared pan, and bake for 10 minutes or until light golden-brown in colour.
Dust a clean tea towel with icing sugar. Loosen the edges of the cake and invert the sponge onto the towel, leaving the parchment paper on. Gently roll the sponge and the towel up together. Cool on a wire rack, seam side down, for 10 - 15 minutes.
For the Cream Filling
Using a handheld or stand mixer fitted with the whisk attachment, mix the heavy cream, icing sugar, and cinnamon together on low speed first, slowly increasing to medium speed and mix until firm peaks form.
Once the cake has cooled, gently unroll, peel away the paper and spread 2/3 of the filling over the cake. Re-roll the sponge without the tea towel and spread the remaining filling on top of the cake. Sprinkle with cinnamon if desired.