Preheat your oven to 350°F (175°C) and grease a standard loaf pan, lining the bottom with parchment paper.

Cream together the softened unsalted butter and granulated sugar on medium speed for about 3-5 minutes.

Slowly mix in the melted semisweet chocolate chips until fully combined, then add large eggs one by one.

Add in sour cream or Greek yogurt and mix on low until well blended.

Whisk together the all-purpose flour, dark unsweetened cocoa powder, baking powder, and kosher salt in a separate bowl.

Whisk together whole milk and vanilla extract until combined.

Gradually add one-third of the dry mixture to the wet ingredients, mixing gently, alternating with the milk mixture.

Pour one-third of the chocolate batter into the prepared loaf pan, layer with graham cracker halves, and repeat two more times.

Bake for 35-40 minutes until a toothpick inserted in the center comes out with a few moist crumbs.

Allow the cake to cool in the pan for about 10 minutes, then release it onto a wire rack.

Combine egg whites and granulated sugar in a bowl over a double boiler, whisk until sugar dissolves, then whip until stiff peaks form.

Spread the meringue over the cooled cake and toast with a kitchen torch until golden brown.

Slice and serve at room temperature.