1-Getting started: Getting started with this high altitude Black Forest sheet cake begins with preheating your oven to 350°F (175°C) and preparing two 9-inch cake pans by greasing and spraying their bottoms with non-stick spray. Gather all ingredients and measure them accurately to set yourself up for success, especially when adjusting for high altitude conditions. This step ensures even baking and helps prevent issues like cracking or uneven rising.

2-Mixing dry ingredients: In a large bowl, sift together the flour, sugar, cocoa powder, espresso powder, baking soda, baking powder, and salt to mix the dry ingredients evenly. This sifting process is key for high altitude baking as it promotes better leavening. In a separate bowl, whisk the eggs, milk, sour cream, oil, and vanilla extract until fully combined, creating a smooth wet mixture.

3-Combining wet and dry: Add the wet ingredients to the dry ones and stir gently until everything is smooth and fully combined, being careful not to overmix. Divide the batter evenly between the prepared pans and bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean and the tops spring back when touched. Let the cakes cool completely before moving on.

4-Preparing fillings and cream: For the cherry filling, combine the cherries, sugar, cornstarch, salt, cherry juice or liqueur, and lemon juice in a pot over medium heat. Simmer while stirring frequently until the mixture thickens, then remove from heat and stir in the vanilla and butter. Cool this to room temperature and chill it for later use. Meanwhile, for the whipped cream, whip the cold heavy cream until soft peaks form, then add powdered sugar and vanilla, whipping until stiff peaks form.

5-Assembling the cake: To assemble, level the cake layers if they are domed, place one layer on a serving board, spread half the cherry filling, then half the whipped cream, and add the second layer. Repeat with the remaining filling and cream, and top with chocolate shavings and fresh cherries. Put it together just before serving to keep everything from slipping. The total time is about 1 hour and 15 minutes, with 30 minutes for preparation and 45 for cooking.