Prep: Preheat the oven to 375F. Line 1 muffin tin with paper liners. Set aside.
Make the batter: Cream together the butter and sugar until light and fluffy. Add egg yolks in one at a time. Mix in the pumpkin puree and sourdough discard until the starter has fully dissolved into the mixture.
226 grams unsalted butter, 400 grams dark brown sugar, 2 egg yolks, 425 grams pumpkin puree, 113 grams sourdough discard
Using a spatula (or with your mixer on the low setting), fold in the salt, baking soda, spices and a third of the flour into the pumpkin mixture. Continue adding in the remaining flour and stir just until all of the flour has been incorporated, don’t overmix or your cupcakes will turn out tough and rubbery.
6 grams salt, 8 grams baking soda, 5 grams ground ginger, 8 grams ground cinnamon, ½ teaspoon ground cloves, ¼ teaspoon ground nutmeg, 300 grams all-purpose flour
Bake: Bake the cupcakes for 18 to 22 minutes or until a toothpick inserted in the centre comes out clean.
Take the cupcakes out of the oven and allow them to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Make the frosting: In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer) add the butter, cream cheese, maple syrup, and powdered sugar. Mix on low until combined, then speed mixer up to high and whip for 1 to 2 minutes or until light and fluffy. Be sure to scrape down the sides of the bowl and paddle to mix throughly so you have a smooth texture.
226 grams salted butter, 118 grams cream cheese, 88 grams maple syrup, 590 grams powdered sugar
Make the topping: In a small bowl, add the cane sugar and cinnamon and stir to combine completely. Be sure to have this ready before frosting the cupcakes so when you sprinkle this on top, it sticks and the frosting hasn’t began to set yet.
14 grams cane sugar, ½ grams ground cinnamon
Assemble the cupcakes: Place a dollop of frosting (about 1 tbsp) on top of the cooled cupcake. Spread the frosting using an offset spatula.
Enjoy and store: Store in an airtight container in the fridge for up to 3 days.