Vegetable Paella

Ingredients

• leek

  white and tender green parts only, halved lengthwise
  1 large
• olive oil

  divided
  ¼ cup
• butternut or acorn squash

  peeled and cut into 1-inch dice
  1 lb
• medium-sized onion

  chopped
  1 unit
• saffron threads
  ¼ teaspoon
• cayenne pepper
  ¼ teaspoon
• Valencia or basmati rice (or regular long-grain rice)
  2 cups
• low-sodium chicken stock
  2 cups
• dry white wine
  1¼ cups
• x 14 ounce can whole tomatoes

  drained and chopped
  1 unit
• x 14 ounce can quartered artichoke hearts (in water)

  drained
  1 unit
• swiss chard

  stems discarded, coarsely chopped
  ½ lb