Makes one loaf cake
Baking spray (or butter and flour)
2 cups flour
1-1/4 tsp baking powder
3/4 tsp salt
12 T room temperature butter
1 cup sugar
4 large eggs
1/2 cup milk
1/4 tsp peppermint extract
4 ounces melted dark chocolate, cooled slightly
1. Preheat the oven to 325 degrees. Stack two baking sheets (or use an insualted baking sheet), and place a loaf pan on top. Spray with baking spray or butter and flour.
2. Whisk together the flour, baking powder, and salt. Set aside.
3. In a stand mixer, beat the butter and sugar for about 3 minutes, until smooth and fluffy. Add the eggs one at a time, beating between each egg. Add the milk and flour mixture on low speed, in alternating additions (flour-milk-flour-milk-flour), beating until just combined between each addition.
4. Scrape down the sides of the bowl and mix briefly to make sure everything is well combined.
5. Transfer half the batter to another bowl. Mix the peppermint extract into half the batter, and the melted chocolate into the other half.
6. Dollop alternating spoonfuls of the batter into the loaf pan, and then run a sharp knife through everything a few times. Don't overmix -- you want distinct swirls.
7. Bake 80-90 minutes, rotating the pan halfway through and tenting the cake with foil if needed to prevent overbrowning. A tester should come out clean when the cake is finished.
8. Let cool in the pan 10 minutes before turning out onto a wire rack to cool.