Preheat your oven to 350°F (175°C) and prepare a loaf pan by greasing and lining it with parchment paper.

Cream the softened butter and granulated sugar until light and fluffy, about 3-5 minutes.

Incorporate the melted chocolate into the butter and sugar mixture until fully combined.

Add the eggs one at a time, mixing well after each, then fold in the sour cream or yogurt.

Whisk together the flour, cocoa powder, baking powder, and salt in a separate bowl.

Combine the milk and vanilla extract, then gradually add to the batter in three parts.

Layer one-third of the batter in the pan, place three graham cracker halves, and repeat until all ingredients are used.

Bake for 35-40 minutes, or until a toothpick comes out with a few moist crumbs.

Let the cake cool in the pan for about 10 minutes before transferring to a wire rack.

For the meringue, whisk egg whites and sugar over a double boiler until dissolved, then whip until stiff peaks form.

Spread the meringue over the cooled cake and torch until golden brown.