In a mixing bowl, cream the dairy-free margarine and salt with a hand mixer until light and fluffy.
Add the confectioners’ sugar gradually, while beating the mixture at a low speed.
Add the remaining ingredients, turn the mixer up to high, and beat until the frosting is smooth and creamy.Chill while you prepare the bars.Preheat oven to 350ºF, and line a 9 x 13 baking pan with parchment paper.In a mixing bowl, cream the dairy-free margarine and sugar with a hand mixer until light and fluffy.
Add the flour and salt and mix until the dough comes together.
Spread the dough in the prepared pan and bake for 20 minutes or until lightly golden brown.
Let the cookies cool completely before cutting them into bars and removing them from the pan.Frost the individual cookies with the dairy-free buttercream icing right before leaving for your picnic or cookout. The icing recipe makes 2-1/2 cups; refrigerate the unused icing for another use. (It’s great on chocolate cake!)Take the prepared strawberries in a separate container and place a few slices on each bar immediately before serving.