Finely grate the zest of 1 large orange until you have 1 tablespoon into a large bowl. Juice the zested orange into the bowl until you have about 1/4 cup juice. Add 1 1/4 cups granulated sugar, 1/2 cup vegetable oil, 1/2 cup whole milk, 2 large eggs, 2 teaspoons vanilla extract, and 1/4 teaspoon kosher salt, and whisk until combined.