"Create a barbacoa beef recipe using 750 g diced beef and a slow cooker. Make it flavorful, balanced, and suitable for an advanced home cook. Use metric units only. Include ingredients and step-by-step instructions for a Ninja slow cooker, with optional serving suggestions. Keep it free of ultra-processed shortcuts and make it realistic for a household of 1 with moderate budget concerns. Aim for a recipe that explains what barbacoa beef is briefly and how to get tender, rich results."