- To make dressing, strain juices into medium saucepan, reserving the juice of one orange for thinning out the dressing later. Gently simmer over medium heat to reduce liquid by half, until bubbles are slow and the mixture becomes syrupy. To test readiness, dip spoon into the reduction; this should slowly slide down spoon, leaving a trail of sauce. Transfer reduction to a bowl and let cool.
- Once the reduction has cooled, whisk in salt and honey. Next, slowly drizzle the olive oil into the reduction, whisking constantly to create an emulsion. The dressing will get thicker as you add oil, so alternate adding oil and fresh orange juice to retain a smooth, sauce-like consistency, rather than a thick mayonnaise-like consistency. The dressing should be tart and tangy.
- To make salad, arrange slices of blood orange in a single layer on a serving plate.
- In a separate bowl, combine the shaved fennel, fennel fronds, red onion, salt, and 2-4 tablespoons of dressing. Toss to coat and marinate the fennel mixture.
- Place the marinated slaw in a loose heap on top of blood oranges. Garnish with pitted picholine olives, drizzle dressing over the salad, on the oranges, and around the plate (to taste), and shave ricotta salata over the top.