Preheat oven to 200C/180C fan/gas mark 5.
Arrange the red onion quarters on a baking sheet and drizzle over the olive oil and balsamic vinegar. Oven roast the red onion for 15 minutes, until beginning to soften.
Add the Tenderstem® broccoli to the tray with the rosemary sprigs and toss in the tray juices. Season to taste with salt and black pepper, then cook for a further 12-14 minutes and serve.
More ways to cook Tenderstem®
Nutrition analysis of recipes featured on the Tenderstem® broccoli website is calculated by a registered dietitian using McCance and Widdowson's The Composition of Foods, Seventh Edition, but may vary slightly depending on the specific ingredients used. Analyses do not include optional ingredients or suggested accompaniments unless specific amounts are given. If there is a range in the amount of an ingredient, the smaller amount is used. When a recipe lists a choice of ingredients, the first is used.