In a saucepan, combine all the cranberry filling ingredients.

Bring the mixture to a boil over medium heat.

Reduce the heat to medium-low and simmer for 2-5 minutes or until the mixture thickens.

Taste the filling (be careful, it’s hot!) to ensure there's no starchy flavor or aftertaste. If needed, continue to cook for a couple more minutes.

Remove from the heat and set aside to cool to room temperature.

In a bowl, combine the flour, baking powder, and salt. Set aside.

In another bowl, cream the butter and sugar using a hand mixer or a metal whisk just until smooth and well combined.

Add the egg, vanilla extract, and lemon zest, then beat just until combined.

Add the dry ingredients and mix with a rubber spatula, or you can use a pastry knife or a fork until no dry ingredients are left and the dough has a clumpy texture. Do not mix it until it’s smooth and homogeneous in texture.

Preheat the oven to 190°C (375°F) and line a 9” x 13” (23cm x 33cm) baking pan with parchment paper so the bottom and the sides are covered.

Take ⅔ of the dough and press it onto the bottom of the prepared pan in an even layer.

Bake for 12-15 minutes or until the dough is no longer shiny and it just starts picking a golden color on the sides.

Remove from the oven and spread the cranberry filling on top of the dough leaving a ½” (1cm) border untouched.

Take the rest of the dough and spread it on top, creating a crumbly topping.

Bake for 20 - 25 minutes or until golden on top of the crumbles and the filling is bubbly.

Remove from the oven and allow it to cool down in the pan to room temperature.

Remove from the pan, cut into squares, and serve.