Prepare blood orange juice. Fresh juice is best, but frozen concentrate can substitute.

Prepare basil oil by steeping basil in olive oil, or purchase pre-made.

Combine blood orange juice, shallots, tarragon, rosemary, and sugar in a saucepan.

Simmer until flavors blend (about 10 minutes).

Add heavy cream and simmer for 1-2 minutes.

Remove from heat and steep for 15 minutes.

Strain the sauce through a fine sieve and set aside.

Cut each zucchini into 4 (1-inch thick) cylinders.

Dice the remaining zucchini for garnish.

Cut out the center of each zucchini cylinder to create a ring.

Reserve the zucchini centers for the custard.

Blanch the zucchini rings in boiling salted water until just tender, then refresh in ice water.

Preheat oven to 325 degrees F.

Mash the reserved zucchini centers.

Whisk egg yolks and cream in a small bowl.

Add mashed zucchini, orange zest, rosemary, and garlic.

Divide the mixture between 4 ramekins and bake in a water bath until just set (about 15 minutes).

Remove the custards from the oven and keep warm.

Reduce oven temperature to 200 degrees F.

Fit each shelled shrimp into a blanched zucchini ring, curling the shrimp.

Skewer the remaining shrimp with toothpicks.

Bring the strained sauce to a simmer over medium heat.

Reduce heat to low.

Gradually incorporate the butter, emulsifying it into the sauce.

Adjust seasoning with salt and pepper and reserve over very low heat.

Heat olive oil in 2 large skillets over medium heat.

Cook diced zucchini in one pan and sliced oranges in the other.

Season zucchini with salt and pepper and cook until golden and tender; keep warm in a low oven.

Cook orange slices just until firm, season with pepper, and keep warm in the oven.

Wipe out the skillets.

Add olive oil to each and heat over medium.

Season the stuffed zucchini and the skewered shrimp liberally with salt and pepper.

Cook the zucchini and shrimp rings in one pan and the skewered shrimp in the other, until shrimp is firm and lightly browned.

Unmold the custards onto 4 large warm plates.

Arrange zucchini and shrimp rings around each custard.

Remove the toothpicks from the shrimp and place 4 shrimp on each plate.

Arrange a slice of blood orange and some diced zucchini on each plate.

Drizzle the plates with blood orange sauce and basil oil.

Garnish with fresh rosemary sprigs and serve.