Preheat your oven to 350°F (175°C). Grease a 9-inch round cake pan with butter and place parchment paper at the bottom.

In a medium mixing bowl, whisk together flour, baking powder, baking soda, ground cardamom, and salt.

Pulse shelled pistachios in a food processor until finely ground.

In a large bowl, beat unsalted butter and granulated sugar until light and fluffy.

Add eggs one at a time to the butter and sugar mixture, beating well after each addition. Mix in vanilla extract.

Blend in plain yogurt and rosewater until the mixture is smooth.

Gradually add dry ingredients into the wet batter, mixing just until combined.

Mix in milk and optional lemon zest until the batter is smooth.

Carefully pour the batter into the prepared cake pan.

Bake for 40-45 minutes or until a toothpick comes out clean.

Cool the cake in the pan for about 10 minutes, then transfer to a wire rack.

Whisk together powdered sugar, rosewater, and water for the glaze.

Drizzle the glaze over the cooled cake and garnish with crushed pistachios and rose petals if desired.