documentclass[11pt]{article}
usepackage[left=1.5cm,top=2.5cm,right=3.5cm,bottom=3.2cm,a4paper]{geometry}
usepackage{xcolor}
usepackage{adjustbox}
usepackage{setspace}
usepackage{blindtext}
usepackage{microtype}

setstretch{1.3}
setlength{fboxsep}{0.4cm} % sets the perimeter around colorbox
newcommand{titleText}{My really really long title goes here}

begin{document}

begingroupsetstretch{2.3}
noindent colorbox{black}{parbox{0.95linewidth}{raggedrighttextcolor{white}{Huge expandafterMakeUppercaseexpandafter{titleText}}}}
endgroup

vspace*{2cm}
blindtext

end{document}