Preheat oven to 350 Fahrenheit. Lightly spray the bottom of a 9 inch springform pan with baking non stick spray. Place a round of parchment paper on the bottom of the pan. In a food processor, pulse the graham crackers to finely ground crumbs. Add the chopped rosemary and pulse a 2-3 times until combined. Pour mixture into a medium sized bowl. Stir in the sugar followed by the melted butter and stir til combined. Mixture will be sandy. 

Bake for 8 minutes. Remove and place on a wire rack to cool. Once cool enough to handle, wrap the bottom and outer sides of the pan tightly with two sheets of aluminum foil.

Set crust aside as you prepare the filling. 

In the bowl of an electric mixer fitted with a paddle attachment or in a large bowl using a hand held mixer, beat the cream cheese and granulated sugar together on medium for 1-2 minutes until the mixture is creamy and smooth. Add the sour cream, blood orange zest, blood orange juice and vanilla extract. Beat til combined. Add the eggs one at a time, beating after each addition and beat only to combine Stop mixing as soon as the last egg has been mixed into the batter. DO NOT OVERMIX as mixing too much may cause the cheesecake to crack while it cools. 

Boil some water. You'll need 1 inch of water in your roasting pan for the water bath, so you will probably need an entire kettle of water. Pour the cheesecake batter on top of the crust. Use an offset spatula, a rubber spatula or the back of a spoon to smooth the top of the cheesecake. Place the pan in a large roasting pan. Pour the hot water inside of the roasting pan and carefully place the pan in the oven. 

Bake cheesecake for 55-70 minutes* or until the center is almost set. When it’s done, the center of the cheesecake will slightly wobble if you gently shake the pan. Turn off the oven. Crack the oven door open slightly. Leave the cheesecake in the oven in the water bath for 1 hour as it cools. Remove the cheesecake from the oven and water bath. Allow cheesecake to cool completely uncovered at room temperature. Once cooled, cover and refrigerate the cheesecake for a minimum of 4 hours or overnight. 

Before serving and while the cheesecake is in the refrigerator, prepare the blood orange curd. Allow curd to cool then use an offset spatula, a spatula or the back of a spoon to spread it on top of the cheesecake. Use a knife to loosen the chilled cheesecake from the rim of the springform pan, then remove the rim. Press the knife against the side of the pan as you go around the pan. Use a clean sharp knife to cut the slices.**

Cover or place leftover cheesecake in an airtight container and store in the refrigerator for up to 5 days.

Separate the yolks from the whites. Zest and juice the blood oranges.

Use a wire whisk to whisk together the sugar and egg yolks in a medium saucepan. Stir in the blood orange zest then gradually stir in the blood orange juice and salt.

Place pan on low heat and stirring constantly with a wire whisk (or use a rubber spatula) until  mixture thickens (it should be thick enough to coat the back of a wooden spoon) and has reached 170 F. Turn heat up to medium and continue to whisk or stir constantly if mixture has not thickened enough after about ten minutes. 

Remove pot from heat, then add the cold, cubed butter. Stir until the butter has melted.

Pour curd into a sealable, heat safe container such as a jar with a lid or a bowl. If you’ve poured it into a bowl, place some plastic wrap directly on top to prevent a skin from forming.