Swiss Chard and Swiss Cheese Tart

Name: Swiss Chard and Swiss Cheese Tart
Ingredients: For the crust (makes twice as much as needed for the tart):; 175 grams (1 1/2 cups) all-purpose flour; 75 grams (scant 2/3 cup) rye flour (light or dark); 1/2 teaspoon salt; 8 ounces (2 sticks) cold unsalted butter, cut into cubes; 4-5 tablespoons ice-cold sparkling water or beer, or as needed; For the tart:; 1 bunch chard (about 3/4 lb), washed and dried; 2 tablespoons olive oil; 1 medium leek, white and light green parts only, thinly sliced; 1 bunch (6-8) scallions, trimmed and thinly sliced; Salt to taste; 2-3 garlic cloves, minced; 2 large eggs; 1/4 cup chopped fresh dill; 1/4 teaspoon ground or finely grated nutmeg; Freshly ground black pepper to taste; 2 cups coarsely grated Gruyere, Emmentaler, or other Swiss cheese (or a mix of cheeses)