Cut the butternut squash into roughly 2 inch (5cm) chunks. Heat the olive oil in a large pot (I use a dutch oven here) on the stove over a medium heat. Once hot, add the squash and a pinch of salt and stir to coat. Cover with a lid and lower the heat to medium-low. Leave to cook, stirring occasionally, until the chunks and soft and starting to break down (about 15 minutes). Remove from the heat and set aside.

Preheat the oven to 180°C fan (350°F).

Place the walnuts and oats in a food processor and blitz until you get a scruffy mealy texture. Add the baking powder, salt, fennel seeds and flour to the food processor and pulse to combine. Add the olive oil and 2 tbsp of the non-dairy milk and pulse together until you get a cohesive dough. You may need to add more milk to get it to come together.

Crumble the dough into the base of a 23-cm (9-inch) springform cake tin (or a loose-based tart tin) and use your fingertips to press it down into an even layer over the base and up the sides of the tin (in a springform tin it should come up about 3cm high). Reserve a little bit of the dough for patching up cracks later on. Prick the crust all over with a fork.

Place the cake tin/tart tin on a baking sheet and then into the oven. Bake for 10-15 minutes until it looks dry. Remove from the oven and use the reserved pastry to patch up any cracks that may have formed. Set the crust aside.

Blend the cooked squash until smooth - you can either do this straight in the pot using an immersion blender (hand blender/stick blender) or by transferring it to a food processor/blender and blitzing, then transferring to a mixing bowl.

Add the remaining filling ingredients and stir together. Taste and season with salt as needed.

Pour the filling into the pre-baked crust. Bake for 15-20 minutes until the top looks set and dry.

Heat the olive oil in a heavy, oven-proof frying pan/skillet over a medium heat. Sprinkle over the sugar in an even layer and then lay the shallots cut side-down over the sugar.

Lower the heat to medium-low and leave to cook until you get a nice brown crust underneath (about 5 minutes). Flip each half over and allow to cook until the other side is browned (about 5 minutes again).

Sprinkle with a pinch of salt and then pour in the balsamic vinegar. Cover with a lid or a piece of foil and transfer to the oven - roast for 15-20 minutes until the shallots are soft all the way through. Remove from the oven and uncover.

Top the cooked tart with some leafy greens (I used baby kale) and the caramelised shallots. Serve warm.