How to Make It
Preheat the oven to 375°. In a food processor, combine the parsley with the chives, vinegar, lemon juice, horseradish, garlic, crushed red pepper, honey, 1/4 cup plus 2 tablespoons of olive oil and 1/4 cup of water and pulse until the herbs are finely chopped. Scrape the chimichurri into a bowl, stir in the mustard and season with salt and black pepper.
Arrange the fennel pieces on one half of a large rimmed baking sheet, keeping the wedges intact. Brush with olive oil and season with salt and pepper. Roast for 25 to 30 minutes, until tender.
In a medium bowl, toss the shrimp with the remaining 1 tablespoon of olive oil and season with salt and black pepper. Spread the shrimp on the other half of the baking sheet and roast for 5 minutes, until just cooked through.
Thread the shrimp onto twenty-four 6-inch skewers and arrange on a platter with the fennel wedges. Serve with the mustard chimichurri.