Preheat oven to 350°F (175°C). Line a 9×13" pan with foil or parchment and spray the lining with nonstick cooking spray.

Make the crust: beat 1 cup (226 g) unsalted butter with a hand or stand mixer until creamy. Add 2 cups (248 g) all-purpose flour, ½ cup (100 g) granulated sugar, and ¼ teaspoon salt. Beat until a dough forms (a hand mixer will take longer). Press the dough evenly into the bottom of the prepared pan.

Bake the crust on the middle rack for 18 minutes. While the crust is baking, prepare the filling.

Make the filling: in a blender or a large bowl, combine ½ cup (119 ml) fresh squeezed orange juice, zest of 1 orange, 1 teaspoon orange extract, 1½ cups (150 g) granulated sugar, ¼ cup (31 g) all-purpose flour, ½ teaspoon baking powder, and 4 large eggs. Blend for a few seconds to about one minute until smooth, or whisk vigorously until fully combined and smooth.

When the crust comes out of the oven, carefully and evenly pour the filling over the hot crust.

Return the pan to the oven and bake for 20–23 minutes, until the filling is set and no longer jiggly in the center.

Remove from oven and cool completely in the pan. Once fully cooled, dust the top with powdered sugar, lift the bars out using the foil or parchment, and slice into bars.