Heat 2 teaspoons olive oil in a medium saucepan over medium-high heat. Add the pancetta and sauté for 8-10 minutes, or until fat had rendered and the pancetta is crispy. Add the shallot and sauté 2 minutes longer.
Stir in the sherry vinegar, maple syrup, and brown sugar. Bring to a boil, then lower the heat to medium and simmer to reduce the liquid by half. This will take 20-25 minutes.
While the glaze is reducing, toss the brussels sprouts with the remaining 3 tablespoons olive oil and salt. Stir to coat evenly coat. Arrange them on a baking sheet in a single layer and roast 20-25 minutes.
Toss the brussels sprouts with the glaze and serve hot.