Preheat your oven to 350°F (175°C).
Grease a 9x13-inch baking pan with butter or line it with parchment paper.
Cream together the unsalted butter and granulated sugar until light and fluffy.
Add the all-purpose flour and salt to the creamed mixture and mix until just combined.
Spread the crust mixture evenly into the prepared baking pan, pressing it firmly into the bottom. Bake for 15-20 minutes, or until the edges are lightly golden.
In another bowl, whisk together the granulated sugar, all-purpose flour, and baking powder for the filling.
In a separate bowl, whisk together the eggs, fresh squeezed orange juice, zest of 1 orange, and orange extract until well combined.
Pour the wet ingredients into the dry mixture and stir until just combined.
Pour the orange filling over the hot crust and return the pan to the oven.
Bake for an additional 20-25 minutes, or until the filling is set and slightly golden on top.
Allow the Orange Bars to cool completely in the pan and dust the top with powdered sugar before serving.