Proper use of baseURL

Hey, my current toml file uses the following configuration:

baseurl = ""
relativeURLs = true
title = "Macrocosm"
languageCode = "en-us"
theme = "simple-a"

In themes/simple-a/layouts/chrome/menu I have <a href="{{ .Site.BaseUrl }}"> which gets rendered as <a href >. Where might I be going wrong?

P.S. I run hugo server to start the webserver.

try .Site.BaseURL . case matters

Also, during development, you should not worry about baseurl since its done on localhost . only generated content made via hugo command in the public directory would have your baseurl.