Marinades using leftover liquid coffee sound like a great idea too. I’ve heard of making redeye gravy with leftover coffee, but I never think to save the leftover coffee from the pot to do so.
Here’s a recipe I found that looks like it might make a similar marinade. The main ingredients are brewed black coffee (I would use cold-brew coffee for a stronger but more mellow flavour), Worcestershire sauce, balsamic vinegar, Dijon mustard, and black pepper. I might consider adding red wine in addition to, or instead of, the balsamic.
I don’t like coffee at all but I don’t mind adding a bit of it to a chocolate cake recipe to make it like, deep-voice chocolate.
When I was staying at my mom’s while she was recuperating from a surgery, she always had coffee left over so I made a random chocolate-cake-with-coffee recipe and it was great! Especially with a lighter whipped frosting.
I used Trader Joe’s Coffee rub and found it pleasing, and it was in stores last time I checked, but it’s apparently seasonal. Here’s a copycat recipe.
1/4 cup ground coffee (medium to coarsely ground)
2 Tbsp. brown sugar
2 Tbsp. garlic powder
2 Tbsp. onion powder
2 tsp. cayenne pepper (can be adjusted to your spice preference)
2 Tbsp. paprika
1 Tbsp. ground cumin
1 Tbsp. salt
Of course, I’d turn UP most of those flavors, and sub smoked paprika or a sharp, but that’s me.
I find this works better with (duh) higher quality coffee. I have also found that marinating beef in a strong and/or smoked tea is an amazing option as well.
I used to work at a restaurant/catering place and our signature dessert was called boule de neige (snowball). Our version was a flourless chocolate cake, with a good amount of coffee mixed in, scooped with a full sized ice cream scoop onto a plate, then covered in whipped cream.
Very old (no later than 1960s?) pastry display photo, Mocha cake, lower right:
Not regional, just a relic. You’re mostly right. Mocha (Mokha) is a city in Yemen noted for coffee exporting, and that’s why the name Mocha originally referred to coffee. Mocha Java coffee beans were said to have chocolatey notes, so that’s how the chocolate/coffee thing is thought to have originated. I don’t know exactly when the shift happened, though google suggests 1700s - 1900s. I certainly had mocha lattes in the late 1970s that included chocolate. But the classical desserts retained the original names with the original meaning of mocha = coffee. I had them growing up, and made them in the 1980s in pastry school and bakeries.
Lenôtre’s Desserts and Pastries, 1977 ed., Mocha Cake:
Better Homes & Garden New Cookbook 1968, Mocha Chiffon Cake:
I’m not sure if this regional or more widespread, but it’s common in Southern California for the donut shops to add coffee to their standard maple icing. Coffee is nowhere in the description, but you can taste it.