Preheat oven to 475 degrees.Line your baking dish with parchment paper. Set aside.Toss Brussels sprouts with olive oil and sea salt in your mixing bowl.Arrange Brussels sprouts (open side down), in a single layer, on your baking dish. Bake for 15 minutes.While Brussels sprouts bake, add vinegar, maple syrup, orange juice, orange zest to your small saucepan. Place under medium for about 4 minutes; stir occasionally. Remove from heat and add butter to the mixture; whisk until melted.Once Brussels sprouts are done baking, let cool for about 5 minutes and place them in your mixing bowl. Pour sauce on top and serve.