I always start by preheating my oven to 350°F so it's fully heated by the time my batter is ready. While it warms up, I grease a 9x13-inch pan generously with butter so nothing sticks once it's baked. This step only takes a minute, but skipping it is one of the easiest ways to end up with a cake that tears when you try to serve it.
In a large bowl, I combine the devil's food cake mix, eggs, cherry pie filling, and almond extract. I stir everything together until it's just combined, making sure there are no dry streaks of cake mix left. The batter will look thicker and chunkier than a typical cake batter because of the cherries, and that's exactly how it should be.
I scoop the batter into my prepared pan and spread it out evenly with a spatula. Then it goes into the oven for 26 to 30 minutes. I start checking around the 26-minute mark by inserting a toothpick into the center. It should come out with a few moist crumbs, not wet batter, but not totally dry either.
Once it's out of the oven, I let the cake cool completely on the counter before doing anything else to it. This usually takes about an hour for me. I know it's tempting to rush this part, but adding whipped cream to a warm cake will melt it instantly and ruin the presentation.
When the cake is fully cooled, I spread whipped topping or freshly whipped heavy cream generously over the entire top. I like to swirl it a bit with the back of a spoon so it looks a little rustic and homemade. At this point, the cake is ready to slice and serve.