Preheat your oven to 350°Fahrenheit/175°Celsius. Grease and line a 9x9 baking pan and set aside.
In a large bowl, whisk together the light brown sugar with the egg for 1 minute until thick and smooth.
½ cup light brown sugar, 1 large egg
Pour in the melted butter, salt and vanilla extract. Whisk to combine.
½ cup unsalted butter, 2 teaspoons vanilla extract, 1 teaspoon kosher salt
In a jug or bowl, whisk the molasses with the hot water until smooth.
½ cup unsulphured molasses, ¾ cup hot water
Fold in the dry ingredients, using a rubber spatula to combine everything. Fold until there are no more streaks of flour. Stir in the hot molasses mixture until well combined. This is a pretty loose batter!
2 teaspoons ground ginger, 1 ½ teaspoons ground cinnamon, ¼ teaspoon ground allspice, ¼ teaspoon ground nutmeg, ¼ teaspoon ground cloves, 2 cups all purpose flour, 1 teaspoon baking soda
Pour the cake batter into your prepared pan. Use an offset spatula to make sure the batter is even. Bake for 25-35 minutes. A toothpick inserted should come out clean or with just a few crumbs. Let the cake cool in the pan.
In a large bowl with a handheld electric mixer, or in a stand mixer fitted with the paddle attachment, combine the butter and cream cheese together. Beat for about 1-2 minutes until smooth.
3 oz full fat cream cheese, ¼ cup unsalted butter
Add the confectioners' sugar, and salt. Beat again for 1 minute until light and fluffy.
2 ½ cups confectioners' sugar, pinch salt
Take the cooled cake out of the pan and spread the cream cheese frosting on top. Add sprinkles if you wish!
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. Room Temperature: I make sure that all of my ingredients are at room temperature before I start the recipe, so pull out all of the ingredients about 2 hours before you start baking.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. Please note, I am using Diamond Crystal Kosher Salt and not Morton Salt, which is a coarse kosher salt and much saltier. Butter: I use European style butter in my recipes. This will make your finished bake much creamier and richer.Molasses: use a mild, unsulphured molasses. I used Grandma's brand of molasses. If you're in the UK, use black treacle. Storage: keep in an airtight container in the fridge for up to 5 days.