Just when you need it, here's a 30 minute cake recipe by Cal Peternell, a chef of Chez Panisse in Twelve Recipes (William Morrow, October 2014)...

...For that special occasion you just remembered as you walked through the door.

PAN CAKE

Maybe you forgot his or her birthday, or maybe you didn’t forget, maybe you never even knew, but jeez, it’s today, really? This cake won’t work for a kid’s birthday—that calls for more . . . of everything—but if you just got home, dinner isn’t even made, and it turns out it is someone special’s day, you just have to bust out a cake, and this one is all from the pantry and requires minimal gear and cleanup. Send him out for a pint of ice cream or suggest she use the shower first—this cake can be in the oven before your celebrant gets back. Thirty minutes later and it’s out and cooling on the counter. Fair warning: this cake is like that guy who never moves out of his parents’ house—born there, no matter how ready it seems, it falls to pieces when you try to get it out. Cut into wedges and lever them out individually, then cover your tracks with vanilla ice cream or plain or chocolate whipped cream (page 267).

1½ cups all-purpose flour
1 cup sugar
1⁄8 cup unsweetened cocoa
½ teaspoon salt
1 teaspoon baking soda
1 teaspoon finely ground coffee beans (optional)
1 teaspoon pure vanilla extract
1 tablespoon red or white wine vinegar
1⁄3 cup vegetable oil

Preheat the oven to 350˚F.

Put the flour, sugar, cocoa, salt, baking soda, and ground coffee beans (if using) in an ungreased 8-or 9-inch round cake pan and stir with a whisk. Make a crater, pour in the remaining ingredients and 1 cup water, and whisk until all the corners are gotten and the batter is smooth.
Put in the oven and start checking for doneness in 20 minutes (see page 252); the cake should be done at around 30 minutes.

Vanilla ice cream really helps pan cake, and so does chocolate whipped cream frosting. Start with 4 ounces of semisweet chocolate, chopped or chips, and 1 pint whipping cream. Put all the chocolate and about 1/2 cup of the cream in a medium mixing bowl and heat over simmering water until the chocolate has melted. Remove from the heat and whisk in the rest of the cream and 1 or 2 teaspoons sugar. Refrigerate until well chilled and then whip until thick and smooth. Be sure the cake is completely cooled before spreading on. If it’s a warm day and you’re not eating the cake right away, refrigerate it or the chocolate cream will melt right off.

(* Recipe excerpted from  Twelve Recipes by Cal Peternell -William Morrow, October 2014)