These little cakes are our new go-to dessert, for so many reasons. They're fast and easy (though they don't look it), and they're great for company or just whenever you need a chocolate fix (pretty much every afternoon). Serve them plain, or topped with a bit of ganache and a sprinkling of pistachios or (our favorite) flaky sea salt.
The crust is most crisp the day it's made, but the pie without the whipped-cream topping and chocolate shavings can be made up to a day ahead and stored in the refrigerator. To cut the pie into neat slices, use a serrated knife.