Preheat your oven to 400°F (200°C). Prepare a baking sheet by lining it with parchment paper or lightly greasing it with olive oil. This step ensures the Brussels sprouts roast evenly without sticking to the pan.

In a large bowl, toss the halved Brussels sprouts with 2 tablespoons of olive oil, salt, and freshly ground black pepper. Make sure the Brussels sprouts are well coated with oil to promote even browning during roasting.

Spread the Brussels sprouts in a single layer on the prepared baking sheet. Roast them in the preheated oven for 20–25 minutes, stirring halfway through, until they are golden brown and crispy on the edges.

While the Brussels sprouts are roasting, melt 1 tablespoon of butter in a small skillet over medium heat. Add the minced garlic and sauté for 1–2 minutes until fragrant but not browned. Stir in the Dijon mustard and lemon juice to create a simple yet flavourful sauce.

Once the Brussels sprouts are roasted and caramelized, remove them from the oven and transfer them to a large mixing bowl. Pour the garlic mustard sauce over the Brussels sprouts and toss to coat evenly.

For added flavour, sprinkle the roasted Brussels sprouts with crumbled bacon (if using). The bacon’s smoky and savoury notes will complement the earthy Brussels sprouts perfectly.

Taste the dish and adjust the seasoning with additional salt, pepper, or lemon juice, depending on your preference. The balance between the tangy mustard, fresh lemon, and rich butter should enhance the natural sweetness of the Brussels sprouts.

Transfer the Brussels sprouts to a serving dish and garnish with freshly chopped parsley for a pop of colour and freshness. Serve immediately, either as a side dish or a light main, accompanied by crusty bread or alongside roasted meats.