Chocolate Chunk Cookies Bars

Ingredients

• ¾ cup plain flour (90 g)
• ¼ tsp baking powder
• ¼ tsp baking soda
• ¼ tsp fine sea salt
• ¼ cup unsalted butter (60 g)
• ¼ cup dark brown sugar (55 g)
• 3 tbsp granulated sugar (45 g)
• 1 large egg yolk
• ½ tsp vanilla extract
• 115 g dark chocolate, chopped (70% cacao)
• flaky sea salt, to sprinkle