Heat 2 tablespoons of olive oil in a Dutch oven over high heat. Add lamb and salt and pepper to taste. Cook stirring frequently until browned. Move cooked lamb to a plate.
Add 1 tablespoon of olive oil to the pan and add the onions, carrots, garlic, and potatoes. Cook stirring frequently until softened.
Stir in tomato paste until completely blended with the vegetables. Thoroughly stir in flour.
Add Guinness and stir to combine with vegetable mixture. Add the lamb back to the pan and stir in beef stock.
Add thyme and rosemary and bring to a boil. Cover and reduce heat to simmer. Cook for 90 minutes – 2 hours.
Remove thyme and rosemary stems and stir in optional frozen peas 5 minutes before removing from the heat.
