Display a list of Recipe Ingredient with the Schema plugin for WordPress https://schema.press/docs-premium/add-schema-org-recipe/

schema-display-list-recipeIngredient.php

<?php //* do not include php tag

/**
 * Display Recipe Ingredient
 * 
 * @since   1.0.0
 * @return  null 
 */
function schema_display_recipeIngredient_78239482379847() {

    $output = '';
    
    $count = get_post_meta( get_the_ID(), 'schema_properties_Recipe_recipeIngredient', true );

    if ( isset( $count ) && $count >= 0 ) {
        $output .= '<ul>';
        for( $i=0; $i < $count; $i++ ) {
            $ingredients = get_post_meta( get_the_ID(), 'schema_properties_Recipe_recipeIngredient_' . $i . '_recipeIngredient_item', true );
            if ( isset($ingredients) && $ingredients != '' ) {
                $output .= '<li>' . $ingredients . '</li>';
            }
        }
        $output .= '</ul>';
    }

    if ( $output != '' ) {
        echo $output;
    }
}