Prepare a graham cracker crust according to package directions and set aside.

1/3 c. freshly squeezed lemon juice
1 can (14 oz.) sweetened condensed milk (not evaporated milk)
1 container (8 oz.) frozen whipped topping, thawed
2 cartons (8 oz.) lemon yogurt
12 to 15 drops yellow food coloring

In a large bowl mix together the lemon juice, milk, whipped topping, yogurt and food coloring. Pour into crust and freeze. Let pie stand in refrigerator to soften before serving. Serves 8 or more.