I did my own experiment, without having tried the original recipe. This is just an adaptation of a standard buttermilk pancake / waffle recipe for the siphon. It's probably not as light as the OP's recipe, but I believe that this approach could be tweaked to be at least as light, and without any cream (or with whatever amount of cream you want to use for flavor/texture; you won't need it as a structural ingredient).
I've eliminated the leavening, since the siphon already fills the batter with bubbles, and added methylcellulose at 0.2% the weight of the liquid. This gels at high temperature, preserving the structure while the waffle cooks, but then un-gels after cooking, when the temperature drops (by the time you eat the waffles, there should be no textural effect from the m.c.. I used Ticacell HV.
135 g all purpose flour
30g spray-dried buttermilk*
12–24g sugar
3g salt
0.6g methylcellulose
300g water*
2 eggs
35g butter
seasoning (spices, vanilla extract. etc)
*or use 1-1/4 cup fresh buttermilk
-melt butter on stove or in microwave
-stir together dry ingredients
-whisk together wet ingredients
-very thoroughly whisk the wet into the dry (alternatively use a stick blender or countertop blender)
-strain into 0.5L siphon
-charge with one N2O charger, shake vigorously, and hold for a minute.
-dispense directly onto waffle maker
