In a mixing bowl or your stand mixer bowl, add the softened butter and the brown sugar. Cream on high for 2-3 minutes until well combined and fluffy.
1/2 (113g) cup unsalted butter, softened, 3/4 (150g) cup brown sugar, packed
Add the sourdough discard, honey, molasses, milk, and vanilla to the butter and sugar. Mix on medium speed until fully combined and smooth.
1/3 (80g) cup sourdough discard, 1/4 (60g) cup honey, 1 tbsp molasses, 1 tbsp milk, 1 1/2 tsp vanilla extract
Add the whole wheat flour, all-purpose flour, baking soda, salt, and cinnamon to the wet ingredients.
1 1/2 (180g) cups whole wheat flour, 1 (120g) cup all-purpose flour, 3/4 tsp baking soda, 3/4 tsp fine sea salt, 1 tsp ground cinnamon
Mix on low until just combined and the dough is smooth and soft. Don't overmix at this stage or the dough will get tough!
Divide the dough into two, and portion out on to plastic wrap. Flatten the dough into small rectangles and refrigerate at least 1 hour.
Overnight Fermentation: For optimal fermentation, allow this dough to rest in the refrigerator for at least 12 hours for the sourdough starter to work it's fermentation magic.