01 - Preheat oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, allowing overhang for easy removal.
02 - In a large bowl, combine flour, granulated sugar, matcha powder, and sea salt. Cut in cold butter using a pastry cutter or fork until mixture forms coarse crumbs.
03 - Evenly press two-thirds of the crumb mixture into the bottom of the prepared pan to form a compact base. Reserve remaining mixture for topping.
04 - In a separate bowl, toss sliced apples with sugar, lemon juice, and ground cinnamon until evenly coated. Arrange apples in an even layer over the crust.
05 - In a small saucepan over medium heat, combine heavy cream, light brown sugar, unsalted butter, vanilla extract, and a pinch of salt. Stir continuously until butter melts and mixture comes to a boil. Simmer for 3 to 4 minutes, stirring constantly, until caramel thickens slightly.
06 - Pour hot caramel sauce evenly over the apple layer. Sprinkle reserved matcha crumble evenly on top.
07 - Bake for 40 minutes, or until crumble topping is golden and caramel bubbles at the edges.
08 - Allow bars to cool completely in the pan. Use parchment overhang to lift bars from pan, then slice into twelve even portions.