Preheat the oven to 350°Fahrenheit/175°Celsius. Grease and line an 8x8 cake pan with parchment paper.
In a large mixing bowl, whisk the sugar with the eggs for 1 minute until you see some bubbles on the surface. Whisk in your Biscoff spread.
Add the yogurt, oil, vanilla extract and salt and whisk once more until smooth.
Fold in your flour, baking powder, baking soda, and spices and fold until smooth.
Pour into your pan. Bake for 30-35 minutes, a toothpick inserted should come out clean. Let it cool in the pan for 20 minutes then remove it and let it cool completely on a wire rack.
In your stand mixer with the paddle attachment, beat the butter and confectioners’ sugar on low speed until well combined. Turn the speed to high for 2-3 minutes until light and fluffy.
Add in the salt, vanilla extract and Biscoff spread and beat again on medium speed for 2 minutes.
Add in the heavy cream a tablespoon at a time until it is the consistency you like.
Notes
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, like Kerry Gold, in my recipes. This will make your frosting much creamier and richer.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.Yogurt: You can substitute the yogurt for buttermilk or sour cream. Neutral Oil: Use an unflavoured oil like rapeseed, canola oil or vegetable oil.Storage: Keep tightly wrapped in the fridge for up to 5 days. Let it come to room temperature before eating.