1. Preheat oven to 350ºF.2. Rub sirloin with olive oil and crushed garlic. Mix pepper and rosemary together and press evenly onto all sides of steak.
3. Place roast on a rack in a shallow roasting pan. Insert meat thermometer so bulb is centered in thickest part. Do not add water or cover.
4. Roast approximately 50-60 minutes (or 16-20 minutes per pound) for medium-rare or medium doneness.
5. Approximately 20 minutes before roast is finished cooking, heat water, sugar and butter in a pan large enough to place the onions in a single layer so they are just touching.
6. Add onions and bring liquid to a boil. Reduce heat to medium. Continue cooking until onions begin to caramelize. Gently toss to glaze all sides.
7. When onions are a deep brown, add orange juice and stir to combine. Remove from heat.
8. Remove roast when meat thermometer registers 140ºF for medium-rare, 155ºF for medium. Let stand 10 minutes. (Temperature will continue to rise to 145°F for medium-rare, 160ºF for medium.)
9. Carve roast into slices and serve with Pearl Onion Jam.