There are different tutorials for rose cakes online, but I found the one at I Am Baker to be helpful. I used a boxed white mix and baked the cake in two 9-inch round pans.
1 cup unsalted butter (2 sticks), softened, but not melted
3 - 4 cups confectioners (powdered) sugar, sifted
1/4 teaspoon salt
1 tablespoon vanilla extract
up to 4 tablespoons milk or heavy cream
Beat butter for a few minutes with the paddle attachment of an electric mixer on medium speed. Add 3 cups of powdered sugar, turn mixer on lowest speed (so sugar doesn't blow everywhere) until the sugar has been incorporated with the butter. Increase mixer speed to medium and add vanilla extract, salt, and 2 tablespoons of milk/cream and beat for 3 minutes. If frosting needs a more stiff consistency, add remaining sugar. If frosting needs to be thinned out, add remaining milk/cream 1 tablespoon at a time.
This makes a creamy smooth frosting.
I found that one batch of this frosting was not enough for this cake. I made two batches.
I put the layers together with frosting, then did a thin coat of frosting over the top and sides of the cake. Then I put the cake in the freezer for a few hours to make it easier to work with.
Next, I did the roses on top of the cake. I believe it would have been better had I squeezed in more roses, because all that empty space has to be filled in with swirls.
My daughter Susan is a dedicated nurse who works very hard at her job. I hope this cake and this birthday will be special for her. Happy birthday, Susan.