Preheat oven to 425°F and line a rimmed baking sheet with parchment paper.
Chop the fronds (leafy green parts) off of the fennel if they’re still attached when you buy it. Discard or save for stock.
Thinly slice the fennel and place it on the baking sheet. Toss with 1 tbsp olive oil and a big pinch of salt, pepper, and garlic powder. Roast for 20 minutes.
Meanwhile, cut the sausages into 5 pieces each, and trim the bottoms off of the baby broccoli if they look brown.
Remove the baking sheet and add the sausages and baby broccoli to the sheetpan. Toss the sausages with a thin coating of olive oil and balsamic vinegar and season with salt and pepper. Drizzle some balsamic over the fennel as well, and toss to coat.
Return the baking sheet to the oven for an additional 15 minutes, until the broccoli is crisp-tender and the sausage is crisped up on the outside.
Serve and enjoy!