Ask a Vegan Baker

I made a single layer vegan chocolate cake from a recipe that calls for 4 8 inch layers. Measurements are metric, so it is easy to just divide everything by 4 to get measurements for one layer. My problem, though, is with greasiness on the bottom of the cake and hardened crust on top and sides. I had to do a fair bit of cutting away in order to make the cake more edible. First time I made the cake, I greased the pan just with oil, no flour, and I think I overdid it. Second cake, I went back to my tried and true method of greasing with shortening and flour. I watched the time very carefully, too, to make sure cake didn't over bake. Not nearly as greasy as first cake, but still, some hardened crust and greasiness on bottom of cake. Here is the recipe for 4 8 inch layers:

640 grams ap flour
688 grams caster sugar
160 grams cocoa powder
3 tsps baking soda
2 tsps baking powder
1 litre coconut or almond milk
600 ml canola oil
6 tsps apple cider vinegar
2 cups frozen raspberries (did not use)

Instructions are to mix dry ingredients together, combine wet ingredients, then add wet ingredients to dry and mix until all is blended. Bake at 350 for approximately half an hour.
I think that for one layer, there is too much oil in recipe which is causing greasiness and hardened edges/top. Just wondering if you had any thoughts about how to improve my results? I've made many vegan chocolate cake recipes and have never had a problem like this, then again, I've never scaled down from 4 layers to one! The cake is really good, nice and fudgy and dense. I'd like to keep it that way. Thanks for any help you can give.