Tuna, Caramelized Onion and Kale Pasta

Ingredients

• • 4 onions, thinly sliced
  • 2 garlic cloves, chopped
  • 3 tbsp butter
  • 2 cans (7 oz/198 g each) oil-packed tuna, drained
  • 2 tbsp (30 ml) whole-grain mustard
  • 1/4 cup (60 ml) dry white wine (optional)
  • 3/4 cup (180 ml) 15% cooking cream or 35% cream
  • 1/2 tsp dried tarragon
  • 1/4 tsp red pepper flakes
  • 1 lb (450 g) bucatini or spaghetti
  • 6 cups (180 g) kale, stems removed, leaves chopped