Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, whisk together the all-purpose flour, whole wheat flour, baking powder, salt, and ground cinnamon until well combined.

Add the cold unsalted butter to the dry ingredients and mix until the mixture resembles coarse crumbs.

Stir in the brown sugar, milk, and vanilla extract and mix until the dough just comes together.

Turn the dough onto a floured surface and knead gently for about 5-6 turns until smooth.

Roll or pat the dough into a rectangle about ½ inch thick.

Score the dough into large squares, ensuring not to cut all the way through, and press a cross pattern into each square.

Transfer the scored dough onto the baking sheet and bake for 20–25 minutes until the edges are golden.

Let the Lembas Bread cool slightly, then break it into squares along the scored lines and serve warm.