For the whole wheat dough
- Add the all-purpose flour, whole wheat flour and salt to a food processor and pulse to combine.
- Add the butter and process until the mixture starts to come together and look like dough and the pieces of butter are the size of a bean.
- Transfer the mixture to a bowl.
- Drizzle with apple cider vinegar and add ¼ cup of cold water.
- Mix with a fork and add as much cold water as necessary for the dough to come together nicely. Cover in plastic wrap and allow to rest for 2 hours.
For the tart
- Preheat the oven to 200* C (390* F) Fan.
- Heat 1 tsp. olive oil in a large pot over medium heat. Add the mushrooms that have been sliced. Season with salt and pepper. Sauté for about 5 minutes stirring constantly.
- Transfer to a small strainer.
- Heat 1 tsp. of olive oil in the same pot. Sauté the garlic for about 30 seconds. Add half of the chard. Season with salt and pepper. Cook until soft and add the remaining chard. Cook for about 5 minutes.
- Remove from heat and season with salt and pepper. Set aside with the mushrooms.
- Place dough onto a lightly floured working surface. Roll out to a 14 cm round shape that is 3 mm thick. Transfer to a baking sheet lined with parchment paper. Crumble the feta cheese over it, leaving the edges clean (like a pizza).
- Add the mushrooms and chard on top and crumble the remaining feta cheese over them. Fold the edges over the filling. Brush some egg wash over the folded edges of dough.
- Bake the galette for about 35-40 minutes until golden brown.
- Remove from oven. Allow to cool a little. Drizzle with some olive oil, lemon juice and grated lemon zest.