In a large bowl, beat the cream cheese and sugar until no lumps remain. Turn off the mixer and scrape down the sides and bottom of the bowl as necessary.
Mix in the corn starch and salted caramel sauce (it should be fully cooled).
Turn off the mixer and scrape down the sides and bottom of the bowl. With the mixer on low speed, mix in the sour cream
In a small bowl, whisk together the 3 eggs and additional egg yolk.
With the mixer on low speed, beat in the eggs until just combined. Be very careful to stop mixing as soon as the eggs are combined.
Place the cheesecake pan (still wrapped in foil) in the middle of a large roasting pan. Pour the cheesecake batter over the crust and smooth the top.
Pour about ½ - 1 inch (around 2 cm) of water into the roasting pan.
Place the roasting pan (with the cheesecake inside) in the oven. Bake for around 60 minutes (it could be anywhere from 50 minutes to 75 minutes). When it's done baking the top should look just set (except for perhaps in the very middle), and if you give the pan a gentle nudge, the middle should wobble like jello or pudding, but not look liquidy.
Turn off the oven and open the oven door. Cool the cheesecake in the oven for 30 minutes, then remove from the oven (with the cheesecake still in the water bath) and continue cooling until it reaches room temperature.
Remove the springform pan from the water bath and cover with plastic wrap or aluminum foil. Place in the fridge to chill for at least 6 hours or overnight.