Mix together the cake mix, water, eggs, and canola oil according to the package directions for the cake mix you're using.
Bake your cake according to package directions and let it cool for 15-20 minutes. Your cake is fully baked when a cake tester or toothpick inserted into the center comes out clean.
While your cake is cooling, mix the Jello mix in a large measuring cup according to the package instructions, first with the boiling water and then with the cold water, mixing until the powder is fully dissolved.
Poke holes all over the top of your cake with a fork, or even the handle of a large wooden spoon. Don't poke too many holes, or else your cake will be completely red, and we're going for red stripes in the cake instead.
Slowly pour the Jello mixture over the entire cake, and allow the cake to finish cooling.
Once cooled, spread whipped cream (or your preferred white frosting) on top of the cake. Then wash (and dry) the berries and add to the top.
Chill the cake for at least 2 hours before serving.