Espresso and Lime

0 Preheat your oven to 350 degrees 
1 Generously butter an 8”x5” loaf pan and line with a parchment paper sling leaving 2-3 inches overhang on both sides 
2 Combine 240 grams of all purpose flour, 30 grams of cornstarch and 2 grams of baking soda in a small bowl and set aside for now
3 In a large bowl, use an electric hand mixer to beat 170 grams of room temperature butter with 4 large eggs until creamy
4 Add 150 grams of sour cream and 2 teaspoons of pure vanilla extract and blend until smooth 
5 Add the flour mixture and mix until just combined
6 In a separate bowl, whisk 78 grams of freshly brewed coffee or hot water with 45 grams of natural unsweetened cocoa powder and 5 grams of espresso powder 
7 Transfer about half of the cake batter in with the chocolate mixture and mix until completely combined 
8 Using a large cookie dough scoop or 1/2 cup measuring cup, add the batter into your prepared loaf pan alternating between the vanilla and chocolate until all of the batter has been added
9 Use a butter knife to swirl the batter a bit
10 Bake at 350 degrees for 60-65 minutes or until a toothpick will come out of the center clean