Heat a large sauté or frying pan on a medium heat. Add the olive oil, onion and garlic with a pinch of sea salt. Gently sweat for 7-10 minutes until soft. Turn up the heat a touch and add the farro or spelt. Toast in the pan for 2-3 minutes before adding the white wine. Cook off the white wine and start adding the stock a ladle or two at a time. Simmer and stir for 25 minutes or until tender to the bite (you may need more stock if the grains are still not al dente; the cooking time can vary). Add the frozen peas and lemon juice and stir in to defrost. Check the seasoning, adding black pepper to taste. Stir in half the Parmesan cheese. If you are feeling naughty, add a knob of butter and stir again. Divide between two plates and top with the remaining Parmesan.