How to use multiple custom post types to archive as front page?

Well, looks like you’ve almost got it. To include multiple custom post types in the WP_Query object, just change:

$query->set( 'post_type', array( 'recipes' ) );

to:

$query->set( 'post_type', array( 'recipes', 'another-custom-post-type' ) );

Basically adding more elements to the array.

So the final code becomes:

function blestrecipes_cpt_filter( $query ) {
    if ( ! is_admin() && $query->is_main_query() && is_home() ) {
        $query->set( 'post_type', array( 'recipes', 'another-custom-post-type' ) );
    }
}

add_action( 'pre_get_posts', 'blestrecipes_cpt_filter' );