Preheat your oven to 350°F (175°C) to ensure even baking.
In your blender, add the eggs, granulated sugar, milk or half-and-half, Original Bisquick mix, and vanilla extract. Blend until well combined and smooth.
Add the softened cream cheese to the blender and blend until silky smooth. Dice the cream cheese into smaller chunks if your blender isn’t very powerful.
Add in the sour cream or Greek yogurt, the additional granulated sugar, and vanilla extract. Blend until creamy and well mixed.
Pour the cheesecake batter into your prepared 9-inch pie or springform pan. Don't worry if the batter seems thin; it will set beautifully while baking.
Bake in the preheated oven for 35 to 40 minutes, until the edges are set and the center has a slight jiggle.
Once baked, let the cheesecake cool at room temperature for about 30 minutes, then refrigerate for at least 2 hours.
Before serving, sprinkle the chopped dark chocolate on top for extra flavor.
