A Fragrant Onion Tart

Ingredients

• 1 1/2lbs onions, about 3 medium
• 2 tbsp butter
• 1 tbsp fresh thyme or 2 pinches dried
• Sea salt
• Freshly ground pepper
• 3 eggs
• 1/2 cup cream
• 1/2 cup milk
• 1 cup grated Gouda or Gruyere cheese
• 1 cup plus 2 tablespoons whole wheat, white or spelt flour
• 1/2 tsp salt
• 6 tablespoons butter, cut into small bits
• 3 tablespoons ice water, more if needed