In a large pot of boiling salted water, cook the brussels sprouts until crisp-tender, about 5 minutes. Drain and pat dry. Cut the brussels sprouts in half lengthwise.
In a large, deep skillet, heat 2 tablespoons of the oil. Add the shallots and cook over moderately low heat, stirring, until lightly browned, 10 minutes; scrape into a bowl.
Add the remaining 1/4 cup of oil to the skillet. Add the brussels sprouts, cut side down, and the pancetta. Season with salt and cook over high heat, stirring occasionally, until the sprouts are browned and tender, 10 minutes. Add the sun-dried tomatoes and shallots and cook, stirring, until warm, 5 minutes. Season with salt, transfer to a bowl and serve.