1. Preheat oven to 400º F. If you have a pizza stone, place it on a rack in the middle of the oven.
2. Pastry:In a food processor, add the flour, sugar and salt; pulse a few times until combined. Add the butter and pulse until the mixture has pea size bits of butter. Add the cold water and pulse just until the mixture just starts to come together.
3. Dump the dough onto a piece of plastic film, flatten into a rectangle, and chill for at least an hour.
4. With a damp towel or vegetable brush, gently wipe the mushrooms to remove any dirt. Remove the dead ends from the stems and slice into slices. Set aside.
5. Wash the Swiss chard, place in colander to drain but do not dry off. Chop the stems into small dice. Set aside. Chop the leaves into bite-size pieces. Set aside.
6. In a medium sauté pan with a lid over medium heat, add the 2 tablespoons of the oil. When warm, add the onions and Swiss chard stems. Sauté until slightly soft, about 4 minutes.
7. Add the garlic and cook an additional minute.
8. Add the leaves stir to combine. Place on the lid and cook for 3-4 minutes until the leaves are wilted.
9. Remove the lid Stir in the thyme and lemon zest.
10. Place the Swiss chard into a bowl. Season with salt and pepper. Set aside to cool.
11. Place the pan back on the fire. Add the remaining 2 tablespoons of oil. Add the mushrooms and sauté until brown and all the water has cooked off; about 4-6 minutes.
12. Place the mushrooms in a bowl and season with salt and pepper and set aside to cool.
13. Place a piece of parchment on the counter. Roll dough out into a 15 x 12-inch rectangle; transfer the dough to a baking pan.
14. Spread the ricotta on the dough, leaving a ½-inch border.
15. Spread out the Swiss chard on top of the ricotta.
16. Sprinkle the mushrooms on top.
17. Using the parchment paper to help you fold the ½-inch border over the vegetables, making pleats. Brush with beaten egg.
18. Place the galette into the 400° F oven onto the pizza stone for 40-45 minutes, until brown.
19. Pull the parchment paper with the tart off the baking sheet and place onto a cooling rack. Cool for 5-10 minutes.
20. Cut into squares, place on platter and serve. Best served warm.
TIPS & TRICKS
• Pastry can be made ahead and kept frozen for up to 3 months in an air tight container or zip lock bag. Defrost in the refrigerator when needed.
• You can use any mushrooms if you like. I used a combo of baby belle and button mushrooms.
• The galette makes a great lunch or picnic food. Serve cold or reheat in 350º oven for 5-8 mins.
• You could add other topping to this galette, like cooked sausage, chopped chicken, or crumbled cheese. I love goat cheese!
• You can also change the vegetables to sautéed zucchini, eggplant, and peppers. Use about 1 cup of cooked veggies. Do not overfill or the crust will be soggy.