2. For caramel, in a saucepan, add sugar ,water, and lemon juice. Bring it to a boil over medium-high heat.
3. Stop stirring, and boil the mixture for about 5 minutes, until it gets a deep amber color. Keep a constant eye, because the sugar mixture tends to burn very quickly.
4. As it gets amber color, immediately remove pan from heat and put it in a pie plate. Swirl and spread it to get a nice even coating.
5. For filling, in a large bowl, add squash, ½ cup sugar, cinnamon, ginger, nutmeg, salt, vanilla, eggs, and egg yolk. Whisk and bring them together.
6. In a small saucepan, heat milk and cream together. Just bring it under the boil.
7. Gradually pour the cream mixture into squash bowl. Whisk it well.
8. Pour squash mixture into pie plate, over the caramel.
9. Take a large roasting pan, fill it with enough water so that it comes halfway upside of pie plate.
10. Place it in oven and bake for about an hour, or until toothpick comes out clean when inserted.
11. Remove the pie plate from water and allow it to cool. Then, place it in refrigerator for 4 hours or overnight.
12. Take a knife, and run around the edge of pie. Invert large plate on top and carefully turn it over.