As I thought: this feature of jetpack (https://jetpack.com/support/featured-content/) is not implemented in a way at dyad2 to show anything else than normal posts.
In inc/jetpack.php
line 17 the function to pull posts for featured content is defined like this:
//Featured content
add_theme_support( 'featured-content' , array(
'featured_content_filter' => 'dyad_2_get_banner_posts',
'max_posts' => 6,
'post_types' => array( 'post' ),
) );
according to jetpack’s feature page this should include recipes as well
add_theme_support( 'featured-content', array(
'featured_content_filter' => 'dyad_2_get_banner_posts',
'max_posts' => 20,
'post_types' => array( 'post', 'rpr_recipe' ),
) );
Manually editing the file might not be the best idea, as each update of the theme will break it. Maybe ask the developers of the theme to add an option to include other posts types as well. Or think about creating a child theme.
Finally: This is not a issue of RecipePress reloaded!