1. Combine ricotta cheese, sugar, milk, flour, lemon juice, lemon peel, vanilla and salt in a bowl. Beat with electric mixer at medium speed until fairly smooth.
2. Add eggs; beat until well combined.
3. Pour into pie crust; bake at 350F for 40 minutes or until center is almost set. Cool completely on wire rack. Cover with dome from graham-cracker crust and refrigerate at least 3 hours.