OK I will save you the effort of Googling for the solution and supply the relevant script so you can mindless copy and paste without doing the research but please read the following thread which is a the result of considerable time spent Googling, trying and testing for a satisfactory solution.
Today I had a eureka for making a page load faster
RewriteEngine On
RewriteCond %{DOCUMENT_ROOT}/_YOUR_CACHE_DIRECTORY%{REQUEST_URI}.html -f
RewriteRule ^(.+)$ /_YOUR_CACHE_DIRECTORY/$1.html [QSA,L]
# OTHERWISE FALL-THROUGH TO PHP, MySQL, Laravel, etc
Please also note that pretty url’s are used and the web-pages must have a .html extension.