Preheat the oven to 375°F (190°C). Line two baking sheets with parchment paper.
In a medium bowl, whisk together the all-purpose flour, baking soda, and salt. Set aside.
In a large bowl, beat the softened unsalted butter, granulated sugar, and light brown sugar with an electric mixer on medium speed until creamy and smooth, about 2 minutes.
Add the vanilla extract and eggs one at a time, beating well after each addition.
Gradually add the flour mixture to the butter mixture, beating on low speed until just combined.
Stir in the semisweet chocolate chips with a spatula.
Divide the cookie dough into portions and roll out on a lightly floured surface to about 1/4 inch thickness.
Using a ruler and a sharp knife, cut out the cookie house panels: two rectangles 8 x 5 inches for the front and back walls, two rectangles 8 x 4 inches for the side walls, and two roof panels 6 x 6 inches with a triangular peak cut out to fit the house shape. Also cut a door and window shapes if desired.
Place the cookie panels on the prepared baking sheets and bake for 12-15 minutes or until edges are golden brown.
Remove from oven and allow the cookie panels to cool completely on wire racks.
While the cookies cool, prepare the royal icing by combining powdered sugar, meringue powder, and warm water in a bowl. Beat on medium speed until stiff peaks form, about 5-7 minutes.
Use the royal icing as glue to assemble the house: pipe a thick line along the edges of the front and back walls and attach the side walls. Hold in place for a few minutes to set.
Attach the roof panels using royal icing along the top edges of the walls and hold until stable.
Allow the assembled cookie house to dry completely for at least 4 hours or overnight before decorating or serving.