Preheat the oven to 375°F.

To par-bake the pie crust, line the crust with parchment paper and fill with pie weights or dry beans. Bake for 15 minutes, until the crust is beginning to look baked and turning light brown. Remove the weights and the parchment paper and prick the bottom and sides of the crust with a fork. Return crust to oven and cook 8 minutes longer. Remove from the oven and brush with an egg wash. Set aside (Brownie filling can be added to a warm or cool crust.) Reduce the oven temperature to 350°F.

In a medium mixing bowl, melt the butter in the microwave. Once melted, whisk the sugar into the hot butter.

In the bowl of a standing mixer, use the whisk attachment to beat eggs for 1-2 minutes, until foamy and pale yellow

Add the cocoa powder, salt, and baking powder to the mixture and whisk an additional minute.

Add the hot butter/sugar mixture to the standing mixer bowl and mix until combined

Add the flour to the batter, mixing just until fully combined.

Fold in the chocolate pieces.

Spread the brownie batter into the par-baked pie crust.

Bake for 35-40 minutes, until just a few crumbs cling to a toothpick/knife when stuck in the center of the brownies. Cover the edges of the pie crust with aluminum foil to prevent overbrowning (I covered the edges about midway through baking.)

Remove from oven and allow to cool for at least 15 minutes before slicing and serving.