An hour ahead of time, unwrap your cream cheese blocks and set them out at room temperature to soften. When the cream cheese is softened, start the recipe.
Move the top oven rack down to the second lowest position in your oven (to prevent over browning the cheesecake), with nothing above it. Preheat the oven to 400 degrees F. Grease a 10-inch springform pan, making sure to coat the sides well. (See notes if you have a 9-inch springform.)
Fill a roasting pan ¼ full with hot water. If you have a leak-proof springform, place it in the water bath. If you suspect your springform will leak, (see notes) place it in a pie dish, then place the pie dish with the springform in the water bath.
In a large mixing bowl, add one block of cream cheese and beat it until creamy. Continue adding one block of cream cheese at a time and beating well, scraping the beaters and bowl as needed. There must not be any lumps in your batter.
Add the eggs one at a time, mixing after each addition on low.
Break up all of your chocolate bars into pieces and add them to a microwaveable bowl. Cover loosely and heat on high in the microwave for a minute, then stir. Heat for another 50-60 seconds and stir. Heat for another 30 seconds or more as needed, stirring afterward until the chocolate is fully melted. Set aside to cool. You will need to wait until all of the other ingredients have been added before you mix in the chocolate.
Add the other remaining ingredients one at a time, mixing to combine after each addition, and scraping the beaters and bowl as needed.
Add the melted chocolate to the batter and mix until combined, scraping the batter and bowl as needed. Then beat on high (or as high as you can without splashing) for seven minutes.
Transfer the batter to the springform pan (filling it no more than ¾ of the way to the top; see notes if you have extra batter). With the springform in the water bath, bake for 10 minutes at 400 degrees F. Then lower the temperature to 375 degrees F and bake for 45-55 minutes. The top should be set, except for a small circle in the middle. Do not insert anything into the cheesecake to test it, or it will crack. Turn off the heat and let the cheesecake stay in the oven with the door ajar for one hour.
Leave the cheesecake in the springform pan and let it finish cooling on a wire rack. Refrigerate the cheesecake overnight before cutting into it. Refrigerate it uncovered if you can, unless you have strong odors in your fridge from onions or something. (See notes.) Store it in the refrigerator for up to three days or cover it with plastic and foil and freeze it for up to 3 weeks.
Slice the cheesecake when it's cold and firm, right out of the refrigerator. It will soften as it sits out and it'll be more difficult to get clean slices. Use a knife dipped in warm water, or use unflavored dental floss. Serve the cheesecake plain or with strawberries, if desired. It's also great with whipped cream.
To test if your springform leaks, place your springform pan in the water bath and wait 10 minutes to see if any water seeps into your springform. If so, dry it, grease it and place your springform in a pie dish. Then place the pie dish with the springform in the water bath.
If you only have a 9-inch springform pan, fill it ¾ full with batter. You will have extra batter to bake in 4-5 ramekins or a baking dish (an 8x6x2 glass pan works well.) Bake the remaining batter in a water bath, ideally in a separate oven so you can pull the ramekins/baking dish out earlier without affecting the cheesecake in the springform. I baked my extra batter in a separate oven for 10 minutes at 400 degrees, then 25 minutes at 375 degrees, then left it in the oven with the door ajar for 20 minutes. If you don't have a separate oven, bake the ramekins/baking dish in the same oven with the springform cheesecake for the full amount of time and just know that the ramekins/baking dish will come out a bit overcooked, but tasty.
Whenever I cover the cheesecake with foil or wrap the first night, a few drops of moisture pool on top of the cheesecake, leaving a water stain on its surface. If you don't have strong odors in your fridge, try leaving the cheesecake uncovered.