Strawberry Volcano Cake

Hello Everyone, 

My niece has asked for a strawberry cake with strawberry filling for her birthday. I have reviewed quite a few recipes online and haven't really found anything to my liking - from scratch and no artificial flavorings like Jell-o.  She has asked that this cake be in the shape of a volcano so it must also be sturdy enough for stacking, carving and covering in fondant. Gotta love the 7 year old mind... :) Any recipes, suggestions or advice on this cake project would be greatly appreciated! 

Anyone know of a way that I can have lava erupt that doesn't involve vinegar/acid that wouldn't ruin the flavor of the cake?