Chocolate Cake in a Jar

Sterilize two straight-sided, wide-mouth, pint-sized canning jars, lids, and rings by boiling for 10 minutes. Keep the lids and rings in hot water until needed.

Preheat the oven to 325 degrees F (165 degrees C).

Meanwhile, mix flour, sugar, baking soda, and cinnamon in a small bowl; set aside.

Combine butter, water, and cocoa powder in a medium saucepan over low heat. Heat and stir until butter is melted and mixture is well blended, 5 to 10 minutes. Pour into a large bowl.

Stir in flour mixture and blend. Add buttermilk, egg, and vanilla and beat by hand until smooth. Stir in nuts.

Distribute batter evenly into the 2 prepared canning jars; place the jars on a cookie sheet.

Bake in the preheated oven until a toothpick inserted deep into the center of cake comes out clean, 35 to 40 minutes.

Using heavy oven mitts, remove cakes from the oven one at a time. Place a lid and ring onto each jar and screw them down tightly. Place the jars on the counter and listen for them to "ping" as they seal. If you miss the "ping," wait until they are completely cool and press on the top of the lid. If it doesn't move at all, it's sealed.