One 20-by-30-inch foam board; brown craft paper (larger than foam board); 2D piping tip and piping bag; fresh flowers such as silver dollar eucalyptus, bud roses, baby's breath or your favorite small flowers
Beat the butter in the bowl of a stand mixer fitted with a paddle attachment on high speed until fluffy, 1 to 2 minutes. With the mixer on low speed, gradually add the confectioners' sugar, alternating with the milk, 1 tablespoon at a time, to adjust the consistency of the buttercream. Add the vanilla and salt and mix on medium-high speed for about 1 minute to lighten the buttercream. Add the buttercream to a pastry bag fitted with a 2D piping tip. Tie off the piping bag with a rubber band.
Cover a 20-by-30-inch foam board with brown craft paper if desired. To arrange the cupcakes in the shape of a wedding dress, line 7 cupcakes in a row at the bottom of the board. Above that, line another row of cupcakes. Keep stacking the cupcakes to form the shape of a dress; the middle row should have 3 to 4 cupcakes for the waist and the second to last row on the top should have 6 or 7 cupcakes and can be placed to show the scoop of the neckline. For the last row, place 1 or 2 cupcakes over the cupcakes on either end to make the shoulders of the dress.
Starting from the middle of each cupcake and working clockwise, pipe roses on each cupcake. Lay greenery on top of the "waist" of the dress and down the right side (I like silver dollar
eucalyptus). Arrange bud roses, or your favorite small flowers, on top of the greenery. Fill in any holes with filler flowers, like baby's breath.