Start by preheating oven to 375 degrees and line a baking sheet pan with parchment paper. Set pan aside
Combine flour, baking soda and salt in small bowl and set aside. In a large mixing bowl, beat Country Crock, granulated sugar, brown sugar and vanilla extract until creamy. Add in egg whites, one at a time, beating well after each addition.
Slowly beat in flour mixture. Stir in morsels and then drop by rounded tablespoon onto parchment lined, ungreased baking sheets.
Bake for 9 to 11 minutes then cool on baking sheets for 2 minutes; remove to wire racks to cool completely.
Once cookies are complete cooled, make your buttercream frosting. In a large bowl, mix together sugar and butter. Once ingredients are combined, mix on medium speed for at least 3 minutes.
Add vanilla and whipping cream and continue to beat on medium speed for 1 minute more, adding more cream if needed. Refrigerate for 10 - 20 minutes depending on spreading consistency.
To assemble, spread a rounded tablespoon filling on flat sides of cookie and top with a second cookie