Begin by preheating oven to 350°F (175°C), and place cupcake liners in baking pans.

Add the flour, sugar, baking powder and salt to a large bowl, and gently combine with a large spoon.

Add in the sour cream, and gently stir until just combined. The batter will be very thick, but that's how it should be!

Next, add in the water, vanilla extract, rose water, egg and vegetable oil, and mix until the batter comes together.

Fill the cupcake liners about 2/3 way full. Bake for 17 minutes, or until a toothpick comes out clean.

Allow the cupcakes to cool for 5 minutes before moving them to a cooling rack to finish cooling. If you want to accelerate the cooling process, pop the pans into your freezer for about 30 minutes.

Beat the butter on a medium speed for 30 seconds with a paddle attachment, until smooth. Slowly add in the powdered sugar in two installments. Alternate with the heavy cream.

Once fully mixed, add in the vanilla extract, rose water, and salt, and beat on low until the ingredients are fully incorporated, and the desired consistency is reached. 

If the frosting is too thick, add in additional cream (1 Tablespoon at a time). If the frosting is too thin, add in more powdered sugar (quarter of a cup at a time).

Place the buttercream in a piping bag fit with your favorite frosting tip, and pipe large swirls onto the fully cooled cupcakes.

Garnish as desired, then enjoy!