Homemade Savory Vegetable Crostata with Swiss Chard and Goat Cheese - Quickie Treats

Ingredients

• 95g all purpose flour, plus more for dusting
• 95g whole wheat flour
• 1/2 teaspoon kosher salt
• 6 tablespoons unsalted butter, cubed and chilled
• 3-4 tablespoons cold water
• 3 tablespoons olive oil, divided
• 6 cloves garlic, peeled and stems removed
• 1 large yellow onion, thinly sliced
• 1 1/2 teaspoons kosher salt, divided
• 2 medium red potatoes, thinly sliced
• 80ml water
• 1/4 teaspoon red pepper flakes
• 2 rainbow swiss chards, stems and leaves separated, thinly sliced
• 225g goat cheese, room temperature
• 1 large egg, beaten