Looks like homemade twinkie cakes!!!
I just looked at the recipe online.
If I were doing it and wanted a more tender result, I would only use the mixer for the eggs/sugar portion. Then I would sift in the flour mixture & stir in the liquid by hand. Traditional method is 1/3 flour, then 1/2 liquid, 1/3 flour, remaining liquid, remaining flour. Fold or stir gently after each addition.
I find that even on very low speed, the mixer works the batter too much for some applications. Less working of the batter = softer results.
If you are really going for a twinkie-like cake, I think I'd try David Leite's recipe, rather than the cakeboss.