1. Make mash
Preheat the oven to 220C, fan-forced. Grease a 1L (4 cup) baking dish. Peel the potatoes and cut into 2cm chunks. Put the potato in a medium saucepan of cold salted water and bring to the boil. Reduce the heat to medium and cook for 10-12 mins until tender. Drain, then return to the pan and mash until smooth. Add 1 tbs olive oil, season with salt and pepper and stir until combined.
2. Brown sausage
Meanwhile, finely chop the onion. Coarsely grate the zucchini. Grate the cheese. Cut the sausages into 1cm-thick rounds. Crumble 1 stock cube* into a heatproof jug, add 180ml (¾ cup) boiling water and stir to dissolve. Heat 2 tsp olive oil in a medium deep frypan over medium-high heat. Cook the sausage, stirring, for 3-4 mins until browned. Remove from the pan.
3. Cook filling
Heat 2 tsp olive oil in the same pan over medium heat. Cook the onion, stirring, for 3-4 mins until softened. Add 1 tbs plain flour and cook, stirring, for 1 min or until golden. Add the sausage, zucchini, stock and worcestershire sauce and bring to the boil over medium-high heat. Cook for 5 mins or until thickened. Remove the pan from the heat.
4. Bake pie
Taste the filling, then season with salt and pepper. Add half of the cheese to the mashed potato and stir to combine. Transfer to the baking dish and spoon over the cheesy mash. Scatter over the remaining cheese and bake the pie for 10-12 mins until the mash is golden and the filling is bubbling.
5. Cook peas and serve up
While the pie is baking, bring a small saucepan of water to the boil. Add the peas and cook for 2 mins or until tender. Drain, then return to the pan. Add 10g butter, season with salt and pepper and stir until the butter is melted. Divide the pie and peas among bowls and enjoy!
6. Make it yours
Like it herby? If you have some on hand in the crisper drawer or veggie garden, add some mint, chives or parsley leaves to the peas.