Cake serves 30. Barn cookie serves 6; each remaining cookie serves 1.
In advance: Make Roll-Out Cookie recipe or use refrigerated sugar cookie dough. Press dough ½ in. deep in Stand-Up House Pan sprayed with vegetable pan spray. Bake 15-20 minutes; let cool on cooling grid 5 minutes. Remove from pan; cool completely. Roll out additional dough; cut boy, pig and horse cookies (Reverse cutter for different looks! Cut dough with knife.). Bake according to recipe; cool on cooling grid.
Bake your favorite cake recipe or mix in oval pan. Cool in pan on wire rack 10 minutes. Remove from pan; cool completely. Place on foil-wrapped cake board. Ice cooled cake smooth with green buttercream. Mark even divisions on cake side; use ribbed side of tip 48 to pipe fence posts and crossbars.
Tint royal icing red, black, dark brown, light brown, skin tone, pink, blue, yellow; reserve some white. (NOTE: If cookies will not be shipped and will be eaten quickly, buttercream icing can be used to decorate cookies.)
Add wood "slats", roof shingles and outline barn door, windows and roof line using basketweave tips. Pipe in windows (smooth with finger dipped in cornstarch). Add a small amount of shredded wheat on window ledges for hay.
Outline and pipe-in body with round tip (smooth with finger dipped in cornstarch). Use tip 5 to accent head, ear and snout. Use tip 2 to pipe-in dot eyes, nostrils and mouth. Add tip 2 curly tail.
Pipe-in body with round tip (smooth with finger dipped in cornstarch). Add tip 3 pull-out mane and tail. Pipe dot eyes, outline mouths and pipe-in hooves. Pipe ears with tip 3.
Using round tips, pipe-in farmer's facial features and hands. Outline and pipe-in shirt, overalls and shoes (smooth all with finger dipped in cornstarch). Add pull-out hair. Use tip 102 to pipe hat and ruffle brim. Pipe tip 2 hat band.
Attach cookie sticks to backs of cookies with royal icing; let dry completely. Insert cookies into cake; trim sticks as needed. Add crumbled shredded wheat at cake bottom.