Drinking bourbon at brunch makes a statement. Is the statement good? Is it bad? I guess it depends on your perspective.
If you want a cocktail at brunch, usually your options are a Bloody Mary or a mimosa. There's nothing wrong with either one, but they're not for me. Even though I love vodka, I don't like a Bloody Mary. Similarly, even though I like some champagne, I don't really care for mixing it with orange juice.
So what if you want something else? Inspired by something I saw in Imbibe magazine, I give you the Good Morning Manhattan.
2 ounces bourbon (I recommend Willett)
1 teaspoon orange marmalade
2/3 ounce sweet vermouth (I recommend Carpano Antica)
2 dashes orange bitters
Combine the bourbon and the marmalade in a shaker, stir until the marmalade is more or less dissolved, add ice and the other ingredients, stir with the attitude that comes from drinking bourbon before noon, then strain into chilled cocktail glass.
This cocktail is definitely not part of a complete breakfast, unless you're Homer Simpson or Peter Griffin. My wife and some friends accurately describe this concoction as "dangerously drinkable." To me this is high praise, and it serves as a friendly warning to you.