Preheat oven to 400 degrees F. Grease a 9-inch pie dish and set aside. Combine all dry ingredients in a large bowl. Melt the butter or ghee and add to the dry mixture and pulse until combined and mixtures look like wet sand. Press into the bottom and sides of the prepared p" pie plate. Bake the crust until set, about 8 minutes or until lightly browned. Transfer to a rack and let cool completely.

Place the butter in a medium bowl. Set the bowl in a larger bowl filled with ice water. Place a fine-mesh sieve over the bowl with butter. Set aside. In another small bowl, whisk the egg yolks. Reduce heat to medium-low, cook mixture, stirring constantly, until mixture is bubbling and thickens about two minutes. Immediately pour the custard over the prepared fine sieve. Press through the sieve into the bowl with butter. Stir until butter is melted and the mixture is cool about 5 minutes. Pour into the chilled crust and cover with a plastic wrap pressing directly onto the surface. Chill until set, about 8 hours.

In a medium saucepan, whisk together sugar, arrowroot powder, and salt with 1 1/2 cup water. Set over medium-high heat and whisking constantly until mixture thickens and bubbling, about a minute.

Slowly whisk in half of the mixture into the egg yolks, orange zest and juice. Reduce heat to low, cook mixture, stirring constantly, until mixture is bubbling and thickens (about 2-3 minutes).

Pour the custard over the prepared fine sieve. Press through the sieve into the bowl with butter. Stir until butter is melted and the mixture is cool about 5 minutes. Pour into the chilled crust and cover with a plastic wrap pressing directly onto the surface. Chill until set, about 4-5 hours.

In a mixer with the whisk attachment, beat the egg whites, vanilla, cream of tartar or irish moss, and salt until soft peaks form, about 3-4 minutes. With the mixer running, gradually add the 2 tablespoons sugar.

Meanwhile, in a small saucepan bring to boil the 1/2 cup sugar, juice, and 2 tablespoons water, stirring until sugar melts. Cook, without stirring for about 4 minutes till it thickens

Remove from heat and gradually pour in the egg whites with the mixer running. Increase speed to high and beat until the meringue is glossy and stiff and the bowl feels cool to the touch. Top the pie with the meringue. Serve as is or use a kitchen torch to toast the top of the meringue.