Preheat the oven to 175°C (350°F). Line a 9x23 cm loaf pan with parchment paper and lightly spray it with non-stick spray.

Brown the butter in a saucepan over medium heat until it turns golden brown, then remove from heat and let cool in a heatproof bowl.

Whisk the cooled browned butter in a large bowl along with brown sugar and granulated sugar until smooth. Stir in the egg, molasses, and vanilla extract.

Sift together flour, baking soda, and spices in another bowl, combining well to evenly distribute the spices.

Fold the dry mixture gently into the wet mixture, then stir in the chocolate chips.

Spread the dough evenly in the prepared pan and top with more chocolate chips for an extra treat. Bake for 25 minutes until golden brown.

Cool the bars completely once out of the oven. Meanwhile, whisk egg whites and sugar over simmering water until dissolved, then whip until stiff peaks form.

Pipe the meringue onto the cooled bars and toast lightly with a kitchen torch until golden.