// Function to set what appears in the loop
function sk_loop_content() {
	remove_action( 'genesis_entry_header', 'genesis_post_info', 12 );
	add_action( 'genesis_entry_header', 'genesis_post_info', 7 );
}

// Function to output the loop
function sk_loop_markup() {
	printf( '<article %s>', genesis_attr( 'entry' ) );

		do_action( 'genesis_entry_header' );

		do_action( 'genesis_before_entry_content' );

		printf( '<div %s>', genesis_attr( 'entry-content' ) );
		do_action( 'genesis_entry_content' );
		echo '</div>';

		do_action( 'genesis_after_entry_content' );

		do_action( 'genesis_entry_footer' );

	echo '</article>';
}

add_action( 'get_header', 'function_to_add' );
function function_to_add() {
	// WP_Query arguments
	$args = array (
		'cat'            => get_query_var( 'cat' ),
		'no_found_rows'  => true,
		'posts_per_page' => '1',
	);

	global $data;

	ob_start();
		$loop = new WP_Query( $args );

		if( $loop->have_posts() ): while( $loop->have_posts() ): $loop->the_post();
			sk_loop_content();
			sk_loop_markup();
		endwhile; endif; wp_reset_postdata();
	$data = ob_get_clean();
}

add_action( 'genesis_before_loop', 'sk_latest_post', 15 );
function sk_latest_post() {
	global $data;
	echo $data;
}