Step 1

Preheat the oven to 400 °F (fan-forced).

Step 2

To a pan on medium to low heat, add 1 tsp of olive oil and the onions. Cook for 5 minutes, stirring regularly. Add the mushrooms, 1 tsp fresh thyme, pinch of salt and pepper, and cook for 15 minutes, covered, stirring regularly. Remove the lid, and cook for a further 5 minutes. Once cooked, set aside.

Step 3

In the meantime, prepare the dough: in a large mixing bowl combine the spelt flour, yogurt, 2 tsp fresh thyme, salt and 1 tbsp olive oil, using a spatula. You will get a crumbly result. Then using your hand knead the dough together for about a minute, until all the ingredients are incorporated, and formed into a ball. Use a little extra olive oil if necessary. The dough will be hard and compact and should not be sticky.

Step 4

Lightly flour a sheet of baking paper, and transfer the dough to the middle. Using a rolling pin, flatten the dough to your desired shape, to be approximately 2 to 3 mm (about 1/10 inch). If you want a perfectly shaped dough you can trim the edges with a knife, otherwise embrace the rustic look!

Step 5

Layer the wholegrain mustard on the dough, leaving about 1.5 cm (0.6 inch) of the outer layer bare for the crust. Top with the cooked onions and mushrooms.

Step 6

Bake in the preheated oven, on the middle to top rack for 30 minutes, rotating halfway.

Step 7

Allow to cool down slightly. Top with the arugula, a bit of crumbled plant-based feta if using, and a drizzle of balsamic glaze. Slice and enjoy!