I don't have an exact recipe, but I wanted to share some of the mental notes I've made while learning gluten-free baking and modifying recipes. There are definitely some great mixes out there these days (it's kind of a fortunate time to be glutenfree and vegan with the booming GF market!), but they're costly and tend to be rice-based. Which is tasty and delicious, but there are a lot of great flours out there, and most of them have a lot more nutritional value, so I try to mix it up when I can.
The cake layers in the pictures behind the cut are actually a de-glutened version of the Faux-stess cupcake recipe from Vegan With a Vengeance. I've found if you convert the weight of gluten flour (125g wheat flour per cup) to an equal weight of gluten-free flours, it's almost perfect, but on some occasions a recipe will require a touch more flour if it seems a little too soupy, so this is no hard and fast rule. (I wish I'd written it down but I'm pretty sure I used sorghum and potato starch for this cake, although it doesn't even matter too much if you go by weight and use roughly 2/3 grain to 1/3 starch, or even less starch than that). Obviously it helps if you like the flours being used! :) My favorite flours for baking sweets so far have been sorghum, millet, corn (flour, not cornmeal or masa), mesquite, almond, and hazelnut. Superfine brown rice flour is pretty amazing, but that's a lot of rice when it's already a dietary staple without all the gluten, so I try to hold back on using it. Sorghum and millet along with a starch (arrowroot, tapioca, cornstarch, or potato starch) has a nice sweet but neutral flavor and are my favorite... everything else seems to require some balancing of flavors by mixing and matching (which is where a lot of the pre-made or store-bought GF blends come in, but I don't really want to make a universal blend). I LOVE the flavors of all these glutenfree flours (I wish I'd branched out years ago!), but there's so many to keep straight, and sometimes I just wish I could run to the kitchen and whip up cookies like I used to, without overthinking what flours go into them. :)
I will also add either 2-3 teaspoons Ener-g egg replacer 1-2 tablespoons finely ground chia seeds in the same color of the baked good (I used Ener-g here, but black chia in chocolate cake is pretty good), and 1/8-1/4 cup very warm water, in addition to any egg substitutes required by the recipe. I try to make all the liquids at least room temp, if not downright warm, and I mix the ever lovin' heck out of the batter. The warmth and the over-mixing develops the grains' proteins a little more and adds some elasticity to the batter. This method can't be used with anything containing xanthan gum (or other gums, I assume) because the batter will turn gummy and the final product may resemble chewing gum. (It's always been edible, but far less enjoyable than my usual gum-free GF baking. Xanthan gum has a bit of a "flavor" to me, and the GF recipes I see online and in cookbooks calling for it always call for FAR TOO MUCH of it. I can get the same effect using the tiniest pinch of xanthan gum, but it still has that creepy weird flavor, so I just started leaving it out and working around it with finely ground chia seeds. Beware using recipes that call for things like yogurt or cream cheeze, because those tend to have gums as thickeners, and it doesn't take much to get the rubbercake effect, even from a little yogurt, so don't overmix those batters!)
Glutenfree baking requires a lot more salt than I'm used to. In the past, I very rarely added salt to baked goods, unless the batter was missing "something," and then I'd just add a small pinch, never the full teaspoon or whatever the recipe called for. Gluten actually does have a bit of a salty flavor to it, and adding salt to GF baking helps balance the flavors out, AND provides a little sciencey kitchen chemistry magic, as well. I also find I often use more sweetener than I used to when baking with gluten, although I've got no logical argument for that change. ;)
(In case it's not obvious, I'm no professional decorator! And for some reason I bought white decorator icing, despite planning white cake frosting....)
inside of the cake! I used a big ol' springform pan: glutenfree vegan chocolate brownie cake (which was really just a double batch of Faux-stess cake, one batch per layer, crumbled and patted down into two layers) with a layer of chocolate peanut butter ice cream, a layer of melted creamy peanut butter, and the second ice cream layer is a chocolate chip cookie dough ice cream. (I used So Delicious coconut milk ice cream, but next time around I might use another brand like Luna and Larry's or maybe even make my own if I'm really ambitious.) I froze each ice cream layer for an hour before moving on, and when I frosted it, I needed to re-freeze a couple times because it was getting a little frustrating when the ice cream melted too much. Frosting ice cream wasn't as easy as I imagined it'd be.