How do I format the post date in Wordpress?

date('n-j-Y', strtotime($recent['post_date']));

This formats it the way you want. Just replace the $recent['post_date'] in your loop with that.

date_i18n('l d/m/Y \à\s g:i', strtotime($item['time']))

Whilst Syfaro's answer is correct, best practice is to use WordPress's own function for this.

get_the_date

This defaults to the format set in the WordPress admin settings (Settings -> General), so gives a more accessible solution for future editing - particularly useful if you roll your code in multiple sites, or more importantly if you release it publicly.

Also, don't forget to escape output - check out esc_html and esc_html_e