One Pot Veggie Pesto Pasta

• 1 tbsp extra virgin olive oil
• 1 brown onion, chopped
• 1 large eggplant, diced
• 285 g roasted capsicum strips (peppers)
• 300 g pasta
• 500 ml vegetable stock
• 0.25 cup pesto
• 100 g baby spinach
• 100 g feta
• 1 tsp chilli (pepper) flakes
• 60 g flaked almonds