In a large bowl, combine flour and brown sugar. Cut in butter until mixture resembles coarse crumbs. Stir in pecans. Press onto the bottom of an ungreased 9-in. springform pan. Bake at 350° for 15-18 minutes or until lightly browned. Cool to room temperature.
In a large bowl, combine marshmallow creme and lemon juice. Stir in strawberries. Fold in whipped cream. Pour over the crust. Cover and freeze overnight or until firm.
Remove from the freezer 20 minutes before serving. Garnish with strawberries and mint if desired.