Melt entire bag of marshmallows with 3 tablespoons of water in a microwavable bowl in 30-second intervals until completely smooth.
Stir in 3 cups powdered sugar until dough begins to form.
Rub hands over shortening and begin to knead the marshmallow fondant. Powder a flat surface with powdered sugar. Knead fondant on flat surface and continue to add remaining powdered sugar until smooth and not sticky.
Divide into 3 balls (small, medium, large). Flatten large ball and add yellow food coloring. Roll and knead until the coloring spreads evenly across ball.
Repeat with second ball (medium) and a combination of yellow and red food coloring to create orange.
Roll balls into rectangular shapes and lay side by side. Press together the layers and roll if needed to desired thin-ness. Cut into triangles!