Sample Code for the Recipe Pattern

Program.cs

using System;
using RecipeStandardLibrary;

namespace ConsoleApp
{
    class Program
    {
        static RefWrapper<string> stringWrapper = new RefWrapper<string>();
        static StringRecipeComposite recipe = 
            new StringRecipeComposite(new RefWrapper<string> { Value = "Hello World" });

        static void Main(string[] args)
        {
            recipe.ProductWrapper.Value = "Hello World!";
            Console.WriteLine(Recipe<string>.FinishedProduct(recipe));
        }
    }
}

Recipe.cs

using System;
namespace RecipeStandardLibrary
{
    public abstract class Recipe<T>
    {
        public RefWrapper<T> ProductWrapper { set; get; }

        public static T FinishedProduct(Recipe<T> recipe)
        {
            recipe.Execute();
            return recipe.ProductWrapper.Value;
        }
        public Recipe(RefWrapper<T> productWrapper)
        {
            ProductWrapper = productWrapper;
        }

        public abstract void Execute();
    }
}

RecipeComposite.cs

using System;
using System.Collections.Generic;

namespace RecipeStandardLibrary
{
    public abstract class RecipeComposite<T> : Recipe<T>
    {

        public List<Recipe<T>> Recipes { get; set; } = new List<Recipe<T>>();
        public RecipeComposite(RefWrapper<T> productWrapper):base( productWrapper)
        {
            
        }

        public override void Execute()
        {
            foreach (var recipe in Recipes) recipe.Execute();
        }
    }
}

RefWrapper.cs

using System;
namespace RecipeStandardLibrary
{
    public class RefWrapper<T>
    {
        public RefWrapper()
        {
            
        }

        public T Value
        {
            get;
            set;
        }
    }
}

StringRecipe.cs

using System;
namespace RecipeStandardLibrary
{
    public abstract class StringRecipe : Recipe<string>
    {
        public StringRecipe(RefWrapper<string> productWrapper):
            base(productWrapper)
        {

        }

        public override void Execute()
        {
            this.ProductWrapper.Value += $"+{this.GetType().Name}";
        }
    }
}

StringRecipe1.cs

using System;
namespace RecipeStandardLibrary
{
    public class StringRecipe1: StringRecipe
    {
        public StringRecipe1(RefWrapper<string> productWrapper): base(productWrapper)
        {
        }
    }
}

StringRecipe2.cs

using System;
namespace RecipeStandardLibrary
{
    public class StringRecipe2 : StringRecipe
    {
        public StringRecipe2(RefWrapper<string> productWrapper): base(productWrapper)
        {
        }
    }
}

StringRecipeComposite.cs

using System;
using System.Collections.Generic;

namespace RecipeStandardLibrary
{
    public class StringRecipeComposite : RecipeComposite<string>
    {
        public StringRecipeComposite(RefWrapper<string> productWrapper) : base(productWrapper)
        {
            this.Recipes = new List<Recipe<string>>{
                new StringRecipe1(this.ProductWrapper),
                new StringRecipe2(this.ProductWrapper)
            };
        }
    }
}