Here is a chocolate cake I think is OK for Lent, as long as Social Tea crackers are ok (?). I suppose if they have dairy in them there are nondairy versions available.
This is my grandmother's "Kekskuchen" or "cookie cake."
Buy 2 packets of Social Tea Cookies. Get a bread pan or square dish and line it with waxpaper. Mix cocoa powder, sugar, a little hot water - my grandmother doesn't use exact measurements, just mix to taste. Heat crisco (I assume this is ok? I suppose any kind of allowed oil would work). Put cookies in dish and spread chocolate mixture over them, then cookies, then chocolate. Top with cookies, cover, and keep in fridge.

Somewhere I have a recipe for brownies that don't have oil or dairy in them...

Here is a non-butter based frosting for my imaginary brownies.
1 1/2c Peanut Butter
3/4 sweetner (we use honey)
1t vanilla
Add PB by T and blend. Put in blender with 1/4c water. Add sweetner and vanilla.