Prep the oranges: Zest one blood orange and set the zest aside.
Juice 2–3 oranges until you have about 1/2 cup. If you like texture, segment one orange to add juicy pieces to the swirl later.
Make the blood orange sauce: In a small saucepan, combine the blood orange juice with 1–2 tablespoons honey and a tiny pinch of salt. Bring to a gentle simmer over medium heat and cook 3–5 minutes, stirring, until slightly thickened and syrupy.
It should coat the back of a spoon. Remove from heat and cool to room temperature.
Sweeten the yogurt: In a bowl, whisk the Greek yogurt with 1 tablespoon honey, the vanilla, and a pinch of salt. Taste and adjust sweetness.
Stir in a bit of zest for extra citrus aroma.
Build the swirl: Spoon half the yogurt into a serving bowl or individual glasses. Drizzle some of the cooled blood orange sauce over the top. Add the remaining yogurt and finish with more sauce.
Use a butter knife or skewer to gently swirl—two or three figure-eights are enough. Don’t overmix.
Add texture (optional): Scatter orange segments, chopped pistachios, or granola over the top. A few mint leaves brighten the whole dish.
Serve or chill: Enjoy right away for a soft swirl, or chill 20–30 minutes to set the layers slightly.
The flavor develops as it rests.