Puree the blackberries until very smooth. Press the puree through a sieve to remove seeds. Set aside.

Pour the whole milk into a large saucepan.

Sprinkle with the gelatin and let sit until gelatin softens, about 5 minutes.

Turn the heat to medium, and cook, stirring until gelatin dissolves and until the mixture simmers.

Add the blackberry puree, heavy cream, sugar, and vanilla.

Cook, stirring, until sugar dissolves.

Divide among 8 ramekins coated with cooking spray.

Cover and refrigerate until set, about 3-4 hours.

Meanwhile, prepare orange curd.

When ready to serve, run knife around edges of ramekins, and invert onto serving plates.

Top with 1-2 tbsp. orange curd.

In a small bowl, whisk together the egg yolks, orange zest, orange juice, sugar and salt. Transfer to a small saucepan.

Cook the mixture over low-medium heat, stirring constantly, until it is thick enough to coat the back of a spoon, 3 to 5 minutes.

Remove from heat and add the butter. Mix until smooth.

Transfer the curd to a small bowl and cover with plastic wrap.

Refrigerate until chilled, about 30 minutes.

Top blackberry panna cotta with orange curd, and serve.