Increase the speed to medium-high and beat for 2 minutes until it becomes very thick. I recommend stopping the mixer and scraping the sides of the bowl so everything is getting mixed evenly.
Stop the mixer and add the salt, vanilla, pumpkin spice, and espresso into the bowl. Beat on medium-high speed for another 2 minutes.
Turn the mixer to your lowest speed and pour in the heavy cream. Beat until it becomes very creamy and spreadable.
¼ cup heavy cream
Assemble your cake and enjoy!
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. I have provided a conversion to US cups but please note that I haven’t tested the recipe with this method. Just click on ‘US Customary’ above the ingredients to see the cup measurements.
I make sure that all of my ingredients are at room temperature before I start the recipe, so pull out all of the ingredients before you start baking.
Butter: I use European-style butter in my recipes. This will make your frosting much creamier and richer.
Pumpkin: you want to use 100% pure pumpkin puree in a can, and not pumpkin pie filling.
Salt: If you don’t have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt.
Buttermilk: If you don’t have buttermilk, replace it with an equal amount of sour cream or full fat yogurt. You can also make your buttermilk, for every cup of buttermilk add 1 tablespoon of lemon juice to 1 cup of milk and let sit for 5 minutes.
Vegetable Oil: Use an unflavoured oil like canola oil if you don’t have vegetable oil.
Storage: Keep tightly wrapped in the fridge for up to 5 days. Let it come to room temperature before eating.
Espresso Powder: make sure you're using fine espresso powder and not coffee granules, that'll be too gritty in the frosting.
Making Ahead: You can make the cake layers ahead of time. Bake them and then once completely cooled, wrap in plastic wrap tightly. Store in the fridge for up to 2 days or in the freezer for up to 2 months. If frozen, allow to defrost and come to room temperature before frosting the cake.