Niatsu

Meat vs. Vegetarian Shepherd’s Pie: A CO2 Reality Check

Marius Semm

Shepherd’s Pie is comfort food at its best – but from a carbon perspective, the classic version with meat comes at a cost. Using Niatsu’s recipe carbon accounting, we compared a traditional Shepherd’s Pie with minced meat to a vegetarian version using plant-based mince.

The result is striking:

  • Meat-based Shepherd’s Pie: 16.2 kg CO2e per recipe (4 people)
  • Vegetarian Shepherd’s Pie: 3.2 kg CO2e per recipe (4 people)

That’s around 80% less CO2 for the vegetarian option – without changing portion size or cooking method. The biggest driver is minced meat, which dominates the footprint in the classic recipe.

You can explore and calculate recipe footprints yourself with Carbon Chef by Niatsu:

👉 https://app.niatsu.com/recipe

Ingredients

Filling

  • 2 tbsp vegetable oil / butter
  • 400 g vegan mince (pea protein–based)
  • 400 g champignons, finely chopped
  • 1 onion, finely diced
  • 1–2 cloves garlic, finely chopped
  • 2 carrots (rüebli), finely diced
  • 2 tbsp tomato purée
  • 200 ml beer
  • 300 ml vegetable bouillon
  • 100 g frozen peas
  • Salt and black pepper

Optional umami boosters (recommended):

  • 1–2 tsp soy sauce or tamari
  • 1 tsp miso paste
  • 1 tsp vegan Worcestershire sauce
  • 1 tbsp nutritional yeast

Mashed Potato Topping

  • 1 kg floury potatoes
  • 150 ml milk
  • 50 g butter
  • Salt

Filling

  1. Heat a little oil in a pan.
  2. Fry the vegan mince until lightly browned, remove and set aside.
  3. In the same pan, sauté onions, garlic, and carrots.
  4. Add champignons and cook until moisture evaporates.
  5. Stir in tomato purée and cook briefly.
  6. Deglaze with beer and vegetable bouillon.
  7. Add vegan mince and peas, simmer gently for about 10 minutes.
  8. Season well.

Mashed Potatoes

  1. Boil potatoes in salted water until very soft.
  2. Drain and let excess moisture evaporate.
  3. Mash finely.
  4. Stir in warm milk and butter, season with salt.

Assemble & Bake

  1. Spread the filling in an ovenproof dish.
  2. Pipe or spread mashed potatoes on top.
  3. Bake at 200 °C for ~25 minutes until golden.

The difference: UMAMI

Meat brings natural umami – removing it means you need to build flavour intentionally. These ingredients make a big difference:

  • Miso paste – deep, fermented savouriness (white or red)
  • Soy sauce or tamari – boosts salt and umami instantly
  • Worcestershire sauce (vegan) – complex, slightly sweet and sour
  • Tomato paste – already in the recipe, but don’t be shy
  • Parmigiano rind (if vegetarian, not vegan) – simmer briefly in the sauce
  • Marmite or yeast extract – small amounts go a long way
  • Nutritional yeast – cheesy, savoury notes
  • Dried mushrooms or mushroom powder – intensifies earthiness
  • Mushroom soy sauce – especially effective with plant-based mince
  • Black garlic – subtle sweetness and depth

The key is layering: use two or three of these together rather than relying on just one.

For this recipe, I used miso paste, soy sauce, Worcestershire sauce, Parmigiano rind, tomato paste, and dried mushrooms.

Takeaway

This Shepherd’s Pie shows how small recipe changes can deliver massive CO2 reductions while keeping taste and comfort intact. For food businesses, these swaps scale fast, and with tools like Niatsu, the impact becomes measurable, transparent, and actionable.

Lower carbon doesn’t mean less flavour. It just means cooking smarter.