Preheat the oven to 220C/200Cfan/Gas 7.
Heat a large heavy based frying pan. Add the olive oil and heat over a medium heat. Add the onion, garlic and tomatoes and fry until slightly soft. Stir in the lemon zest, oregano and vegetable stock. Season with some salt and pepper and cook for around 3 minutes.
Then stir through the cooked orzo and add the dill, peas and black olives, and check the seasoning. Stir again and top with the Feta. Bake in the oven for 5-7 minutes until the Feta has just started to colour.
Scatter over some more chopped dill to serve.
Tip: this dish is also lovely with toasted pine nuts or sunflower seeds. The Feta can be replaced with vegan Feta.