For more than a decade, Cornersmith's Alex Elliott-Howery and Jaimee Edwards have devoted their lives to teaching people traditional cooking skills.

Making and serving pickles and preserves has been a common theme across their cafes, workshops and cooking school.

But over the years the pair have refined their focus – from less bottling tomatoes, to more tips and tricks to keep kitchen scraps out of the bin, and recipes that are versatile enough to stretch over a few dinners.

"We haven't given up on the home-made everything, but we've learned how to cut corners, focus our priorities and develop 'hacks' for both sanity and sustainability," Elliott-Howery and Edwards write in their fourth cookbook, The Food Saver's A-Z: The Essential Cornersmith Kitchen Companion.

Their recipes don't follow a traditional structure: instead, Elliott-Howery and Edwards want to bring resourcefulness back into the kitchen with basic, flexible recipes using ingredients people already have at home.

"We want to encourage you to be a more confident and instinctive cook, to take creative liberties with what you have and what you like."

Here are four easy ideas to try at home.

Oven-baked ratatouille for wrinkly summer vegetables

When the garden or fridge is full of ageing summer vegetables, make ratatouille. This oven-baked version chars the vegetables first to intensify their flavour – and the high heat will hide all the vegetables' imperfections. Serve ratatouille with eggs, stirred through pasta, with sausages, on toast or with grilled (broiled) fish.

Preheat the oven to 180 fan-forced (200C conventional). In a roasting tin, put 1kg roughly chopped summer vegetables – a mix of zucchini, eggplant, capsicum, and red or brown onion. Drizzle ¼ cup (60ml) olive oil over everything and sprinkle with salt, then roast for 30-40 minutes, until soft and starting to char on the edges.

Meanwhile, lightly oil 4 large tomatoes (about 650g) and place in a separate roasting tin. Add to the oven and blacken for about 30 minutes. Once they're jumping out of their skins, remove from the oven and allow to cool a little.

Reduce the oven temperature to 160C fan-forced (180C conventional). Roughly chop the tomatoes, remove any big bits of tough skin or core, and add to the charred vegetables with 2 tsp crushed coriander seeds or crushed fennel seeds, ½ tsp salt, lots of ground black pepper and another 2 tbsp oil. Mix everything together and return to the oven for 15-30 minutes, depending on how tender you like your ratatouille. Taste and add more salt and pepper if needed. Serve hot or cold.

Serves 4-6

Green things fritters

Long live the fritter. Could there be a more forgiving and useful trick up your sleeve? When in doubt, make fritters. When the fridge needs a clear out, make fritters. When the vegie patch is looking like it could do with a tidy-up, make fritters. Here's a green fritter recipe for all of the above. Use spinach, silverbeet, zucchini, kale, celery leaves, peas, herbs, or a mix of what you have.

Finely chop 1 bunch (about 350g) spinach. You can include the stems, but make sure to chop them small (you'll need about 3 firmly packed cups in all). Put the spinach (or other greens) in a bowl with 1 cup picked fresh herbs of your choice, ½ cup grated or crumbled cheese (halloumi and strained feta cheese work well), ¼ cup (35g) plain flour and 3 eggs beaten with ½ tsp salt. Mix all the ingredients very well. Heat 2 tbsp oil in a frying pan over medium-high heat and pour in ½ cupfuls of the green mix, cooking 2-3 fritters at a time for 3 minutes on each side.

Serve the fritters warm, but they're also great the next day for a packed lunch.

Makes 5-6

Big grain salad

A grain salad is healthy and filling, and you can use this and that from the fridge. Grain salads are great to have under your arm when arriving at a barbecue, they make perfect dinners on hot summer nights, and any leftovers for lunch are always welcome. Add pumpkin and feta to your grain salad and make like the 1990s – why not?

Start by cooking your grain(s). You'll need 2-3 cups cooked grains: about 390g-585g quinoa, 330g-495g cous cous or 290g-435g barley. The trick to this salad is making a flavour base with spiced onions. The onions bring a complementary texture to the grains, as well as flavour, so you don't need to make much of a dressing. Heat ¼ cup (60ml) oil of your choice in a small frypan over medium heat then saute 2 large sliced onions with a pinch of salt until translucent and collapsing. This will take 15 minutes or more. Add 4 finely chopped garlic cloves and continue to saute. Now add seasoning according to the flavour profile you want. For this quinoa version, we add 1 tsp ground cumin, 1 tsp dried oregano, 1 tsp chilli flakes or powder, and ½ tsp each of salt and pepper. (If using barley or buckwheat, you might want to change this to dill, tarragon and caraway seeds.) Add ¼ cup (40g) currants and ¼ cup (60ml) red wine vinegar, then continue to saute until the onions are very well cooked and browning on the edges. This always takes longer than you think, so keep going.

Remove from the heat and add your 2-3 cups cooked grain(s), mixing well to coat in the pan juices. Transfer to a large mixing bowl and add ½ cup toasted nuts or seeds and 1 large handful of torn herb leaves. Match the herbs to the seasoning you've used. In this version, we like to use a mixture of coriander and mint, but parsley would work well too. Mix all the ingredients together, taste then add more salt and pepper, and a good squeeze of lemon juice or a little more vinegar. Transfer to a serving bowl or platter.

Serves 4 as a main, 5 as part of a shared meal

Pasta frittata

Now before you skip over this recipe because it sounds a bit ordinary, give this pasta frittata a chance. It's garlicky and parmesany and no one complains when you serve it. It's good for simple minimal-ingredient dinners, cuts well for lunch boxes and reheats for breakfast. And it uses up the strange amounts of cooked pasta in the fridge – penne, shells, even spaghetti. Here we mean cooked pasta with no sauce; a little oil and salt and pepper is OK, but please don't make this with left-over spaghetti bolognese.

Preheat the oven to 160C fan-forced (180C conventional). In an ovenproof non-stick frying pan, heat ⅓ cup (80ml) extra virgin olive oil over medium-low heat. Add 4 sliced garlic cloves and cook gently until fragrant but not burnt. Add 1-3 cups (about 175g-525g) cooked pasta and saute the pasta with the garlic for 1-2 minutes. Add ¼ tsp each of salt and pepper, and mix well. Reduce the heat to low and cook, covered, for 10 minutes, shaking the pan often to avoid burning.

In a medium bowl, whisk 10 eggs with ½ tsp each of salt and pepper and ⅓ cup (35g) finely grated parmesan. Remove the lid and spread out the pasta to cover the base of the frying pan evenly. Turn up the heat to medium and pour in your eggy mix. When the edges frill up a little, reduce the heat again and cook for 10 minutes, until the egg mixture is almost set – it will still be liquidy on top. Top the frittata with extra cheese and then transfer to the oven and let the top cook through. Once it's ready, carefully slide the omelette upside down onto a plate. Serve with a green salad and an onion relish.

Serves 4-6

This is an edited extract from The Food Saver's A-Z by Alex Elliott-Howery and Jaimee Edwards. Photography by Cath Muscat, illustrations by Mirra Whale. Murdoch Books RRP $49.99. Buy now