1. Toss Savannah Smiles into food processor and turn onto lowest setting to crumble cookies.
2. Melt stick of butter and drizzle over crushed cookies.
3. Using pulse setting, mix until all the lemony cookies are covered in butter.
4. Press Savannah Smiles crust into mini cheesecake pan. This is a very handy little pan to have indeed. Bake in a preheated oven at 350F for about 8-9 minutes. When done, set aside to cool.
5. To make filling, place sugar, cornstarch and salt in medium saucepan. Measure cream, milk and eggs and set aside.. Using a microplane grater, zest lemon rind into a bowl. Add lemon juice to bowl as well. Set aside.
6. Have your ingredients ready to go – you know, like a good Girl Scout.
7. Whisk cream, milk, eggs and lemon juice into sugar, cornstarch and salt. Whisk together very well. Add butter. Continue to whisk while cooking on medium-low heat. When it begins to boil, remove from heat.
8. After lemon filling has cooled, whisk the yogurt into the filling until well mixed.
9. Place a scant 1/4 cup of filling into each tart pan. Smooth tops just a bit. Freeze for about 1 1/2 hours.
10. Remove tarts from pan and remove metal piece from the bottom of each tart.
11. Make fresh whipped cream and place into a decorating bag with a large border tip.
12. Swirl whipped cream on top of each tart. For fun, you can add a Savannah Smiles on the top and cut paper straws into thirds and serve in matching cupcake liners.