Heidi mentioned in the comments that coffee and chocolate are reputed to go well together and asked if I had any experience mixing them. Yes, I have, perhaps most successfully in a rich chocolate cake calling for hot water, for which coffee is a “duh” substitute. Several years ago my sister and I made this cake for a Valentine’s dinner for my parents. I made it again more recently and must add a disclaimer. It is probably the moistest and best chocolate cake I’ve ever made, or even tasted (thus was my father’s claim, but who knows if he was indulging us); however, both times I have made it, it has crumbled terribly in the midst of stacking and then cutting the layers. It could be that I did something wrong in assembling it, or it could be that the cake is so moist that it is impossibly delicate. Once I looked up an index of baking problems to see what this crumbling tendency could mean. The helpful answer? “Too much fat.” HA. Sorry, not going to modify that. So, in sum, don’t count on this cake being presentable the first time around—just delectable.

(You could fit the batter into 2 10″ cake pans—or if your 9″ pans are 2″ deep, those would work—and see if thicker layers prevent crumbling. It will need to bake about 10 minutes longer if you use just 2 pans. In case of utter structural collapse, go ahead and make a dessert soup out of milky icing and chocolate “croutons”. Tell any snobbish guests that it’s become all the rage in Paris.)

Chocolate Velvet Cake (from a 2003 edition of Southern Living)
1 1/2 c. semisweet chocolate chips
16 oz. light brown sugar
1 stick butter, softened
2 c. all-purpose flour, sifted (measure the flour after you sift it onto wax paper)
1/2 tsp salt
1 c. hot water or coffee (preferred!)
3 eggs
1 tsp baking soda
8 oz. sour cream
2 tsp vanilla

Melt chocolate in microwave or over double boiler. In a large bowl, beat butter and sugar together at medium speed for about 5 minutes. Add eggs and beat just until blended after each addition. Mix in the chocolate.

Sift together flour, baking soda, and salt. Gradually add to butter mixture alternately with sour cream, beginning and ending with the flour, at low speed just until blended. Gradually add 1 c. hot water or coffee in a slow, steady stream, just until blended. Stir in vanilla.

Spoon batter into 3 greased and floured 9″ cake pans. Bake at 350 degrees for 25-30 minutes. Cool in the pans on a wire rack for 10 minutes; remove layers from pans and let cool completely on the rack.

Here’s a buttercream frosting suggestion, to yield 6 cups (you might have a bit extra).
1 c. unsalted butter, softened
2/3 c. milk
32 oz. powdered sugar
1 Tbsp strong brewed coffee
Cream butter; gradually add sugar alternately with milk, beating at low speed after each addition until blended. Stir in coffee. Frost your cake.