In the bowl of your stand mixer, whisk together 100g (⅓ cup + 1 Tbsp) milk, 75g (6 Tbsp) sugar, 150g (⅔ cup) pumpkin purée, 1 egg, 100g (½ cup) sourdough discard, and 1 tsp instant yeast until smooth.

Add 350g (2 ¾ cups) bread flour and mix just until a shaggy mass forms with no dry streaks left in the bowl. Cover and let it rest for 30 minutes.

Attach your dough hook or spiral attachment (depending on your mixer), add 7g (1 ¼ tsp) salt and mix on low-medium speed for 3-5 minutes.

Turn the mixer up to medium-high and add 42g (3 Tbsp) soft butter in three separate additions, letting each one fully incorporate before adding the next. This takes about 10 minutes total.

Cover the bowl and let the dough bulk rise by 50% at room temperature performing two rounds of stretch and folds spaced 30 minutes apart early in that window.

When the dough has risen by about 50%, grab a small bowl and stir 200g (1 cup) brown sugar, 1 Tbsp cinnamon, and 85g (6 Tbsp) softened butter together until you have a smooth, spreadable paste.

Turn the risen dough out onto a lightly floured counter and roll or press it into a neat 9×17-inch rectangle. Spread the cinnamon filling evenly over the entire surface, all the way to the edges. Using a pizza cutter, slice the dough into roughly 3×3-inch squares.

Line a 9×5 loaf pan with parchment paper. Stack the squares on top of each other like a deck of cards, then tip the whole stack onto its side into the pan. Press down gently to settle everything and fill out the pan evenly.

Cover the pan loosely and let it proof in a warm spot until it’s fully doubled in size.

Preheat your oven to 375°F (190°C). Right before it goes in, warm up ¼ cup of heavy cream in the microwave for 10-15 seconds and pour over the top of the loaf. Bake on the middle rack for about 40 minutes, until the top is a rich, even golden brown.

Let the loaf cool on a wire rack before icing it.

Using a handheld mixer or a whisk, beat 57g (¼ cup) softened butter, 113g (4oz) cream cheese, and ½ tsp vanilla together until smooth. Add 120g (1 cup) powdered sugar and beat until fluffy, then whisk in up to 60g (¼ cup) milk or heavy cream just to loosen it to a soft, pourable consistency. Drizzle generously over the cooled loaf.