Vegetable macedonia: Sweat onion in olive oil. Add potato; cook until edges turn translucent. Add bell pepper, shiitake, and celery in stages. When moisture evaporates and veg begin to caramelize, deglaze with red wine vinegar. Cool.
Shrimp skewers: Thread shrimp onto the rosemary stick; season with salt and pepper. Bake on a parchment‑lined tray at 400°F for 6–8 minutes, just until opaque.
Finish: Spoon macedonia on plate, top with the shrimp skewer, and drizzle lightly with balsamic glaze.