Heat olive oil in your pot over medium heat. Add onions, carrots, and celery, and sauté for 5-7 minutes until softened.
Add halved mushrooms and cook for another 5 minutes until they release their juices.
Stir in garlic, thyme, oregano, and sage. Cook for 1-2 minutes until fragrant.
Sprinkle flour over the veggies and stir quickly to coat. Cook for another 1-2 minutes.
Slowly pour in vegetable broth while stirring to prevent lumps.
Add tomato sauce, balsamic vinegar, soy sauce, bay leaves, potatoes, lentils, salt, and pepper.
Seal the pressure cooker lid and cook under pressure for 15-20 minutes.
Allow natural pressure release to keep veggies tender and broth thick.
Serve hot with fresh herbs or crusty bread.
Notes
Swap baby yellow potatoes with sweet potatoes for a sweeter twist, or use pre-sliced mushrooms to speed things up. Store in fridge up to 4 days or freeze up to 3 months.