Preheat oven to 350 degrees and line 6 muffins tins with muffin lines.
Beat cream cheese, Splenda and lemon juice until blended and smooth.
Melt the chocolate in a large bowl in 20 second intervals in the microwave, stiring between each interval, until melted.
Add the melted chocolate, Greek yogurt, egg white and vanilla into the cream cheese mixture and beat until well blended.
Divide the batter evenly between the 6 muffin tins and bake for 20 minutes, or until the cheesecake feels just set
While the cheesecake bakes, it's time to make the topping.
In a medium bowl, mix together the Greek yogurt and Splenda.
Once the cheesecake has baked until just set, divide the topping evenly among each and spread it over the top gently.
Turn the oven temperature down to 250 and bake for 5 minutes more, until the topping feels just set.
Let the cheesecakes cool completely and then refrigerate over night or for at least 5 hours.
If you want to make the hearts:
Line a small cookie sheet with parchment paper.
Melt the white chocolate in 20 second intervals in the microwave, stiring between each interval, until melted.
Stir in as much strawberry jam as you want to reach the desired shade of pink.
If the mixture becomes to thick, thin it with a splash of fat free half and half or milk.
Spoon the melted chocolate into a pastry bag (or just use a plastic sandwich bag and cut one of the corner tips off) and pipe hearts onto the parchment paper.
Freeze until hard, about 5-10 minutes, and stick on top of each cheesecake.