Preheat your oven to 350°F (175°C) and prepare three 9-inch round cake pans by greasing them.

Cream together the softened unsalted butter, granulated sugar, and brown sugar in a stand mixer until light and fluffy.

In a separate bowl, whisk together the all-purpose flour, ground cardamom, baking powder, and kosher salt.

Gradually combine the dry mixture with the wet mixture, alternating with the milk, orange juice, orange zest, and vanilla extract.

Pour the batter evenly into the prepared pans and bake for about 40 minutes, or until a skewer inserted comes out clean.

Let the cake layers cool in the pans for 10 minutes, then transfer them to a wire rack to cool completely.

Beat the softened unsalted butter with sifted confectioners sugar until fluffy, then add rosewater, vanilla extract, milk, and salt.

Assemble the cake by leveling the layers if necessary, adding rose buttercream between layers and frosting the top and sides.