Whip cream cheese and greek yogurt together until smooth.
Add zest and juice of one lemon and mix until smooth. Taste and adjust the amount of lemon zest and juice.
Put large mixer bowl in freezer for about 15 minutes. Add sugar and whipping cream to bowl and whisk on high just until stiff peaks form. Careful not to over mix.
Break up or crush shortbread cookies and layer into 4 parfait glasses or bowls.
Layer lemon cream cheese mixture on cookies and then whipped cream. Start with cookies and add one more layer ending with whipped cream. Garnish with cookie crumbs and lemon slice.