Melt the Butter: In a small saucepan, melt the butter over low heat.
Mix Honey: While the butter is melting, add the honey to a medium mixing bowl.
Combine Butter and Honey: Once the butter is melted, pour it into the bowl with the honey and mix until smooth.
Incorporate Eggs: Add the eggs to the mixture and mix until fully incorporated.
Add Wet Ingredients: Stir in the sourdough discard, milk, mashed overripe bananas, and vanilla extract. Mix until smooth.
Combine Dry Ingredients: Mix whole-grain flour, all-purpose flour, salt, baking soda, nutmeg, and coffee grounds in a bowl— add to wet ingredients and mix just until combined.
Fold in Chocolate Chips: Gently fold in the chocolate chips, being careful not to over-mix.
Ferment the Batter: Cover the finished batter and place it in the fridge for 12-36 hours for long fermentation (you can skip this step and proceed to the next if you're short on time).
Preheat the Oven: Preheat your oven to 450°F (232°C).
Prepare the Loaf Pan: Coat an 8" x 4" loaf pan with non-stick spray, line it with parchment paper, use a silicone form, or grease and flour it.
Pour the Batter: Remove the fermented batter from the fridge and pour it into the prepared loaf pan.
Bake: Place the loaf pan in the hot oven, then immediately turn the temperature down to 325°F (163°C). Bake for 60-70 minutes, or until a toothpick inserted into the centre comes out clean.
Cool and Serve: Once done, remove the loaf from the pan, transfer it to a cooling rack, and allow it to cool before slicing and enjoying.