Whisk together the olive oil, lemon juice, sugar, salt, and mustard until the sugar is completely dissolved. Taste and add more lemon until it has enough of a lemon flavor for you. Add in some honey if it becomes overwhelmingly acidic.
2/3 cup olive oil, 1/3 cup lemon juice, 1/4 cup granulated sugar, 1/4 teaspoon kosher salt, 1 teaspoon ground mustard