Failing PECS conversion

pecs.java

package io.robusta.java.pecs;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * Created by nicorama on 20/07/2017.
 */
public class ContravariantHeritage {

    public static void main(String[] args) {
        new ContravariantHeritage().launch();
    }
    
    void launch() {
        // With super, you don't care what is already in the list
        // as long as it will allow a Thing to be added;
        List<? super Bamboo> pandaFood = new ArrayList<>();
        pandaFood.add(new Bamboo());


        List<Bamboo> food = new OhPanda().getMeals();    }


    abstract class Restaurant {
        Kitchen kitchen;


        public Restaurant(Kitchen kitchen) {
            this.kitchen = kitchen;
        }

        List<? extends Food> getMeals() {
            List<Food> food = new ArrayList<>();
            this.kitchen.build(food);
            return food;
        }
    }

    interface Kitchen {
        void build(List<? super Food> dessert);
    }

    class PandaKitchen implements Kitchen{

        @Override
        public void build(List<? super Food> dessert) {
            // PandaRestaurant is a Producer, but here we talk about List
            // the List IS a consumer of bamboos
            System.out.println("miam");
            dessert.add(new Bamboo());
        }

    }

    class MeatKitchen implements Kitchen{

        @Override
        public void build(List<? super Food> main) {
            // PandaRestaurant is a Producer, but here we talk about List
            // the List IS a consumer of bamboos
            System.out.println("miam");
            main.add(new Meat());
        }
    }


    class OhPanda extends Restaurant {

        public OhPanda() {
            super(new PandaKitchen());
        }

        /**
         * Huge difference between parameter and return
         * a return from extended class can be more precise than Original
         * But as a param, the contract MUST be the same
         * Example: the equals() function
         */
        @Override
        List<Bamboo> getMeals() {
            List<? super Food> bamboos = new ArrayList<>();

            this.kitchen.build(bamboos);
            return bamboos;  /// <<<==== FAIL: would NOT compile
        }
    }


    class Food {
        @Override
        public String toString() {
            return this.getClass().getSimpleName();
        }
    }

    class Meat extends Food {

    }


    class Bamboo extends Food {

    }
}