Season lamb with salt and pepper. Set aside.
In a large Dutch oven, heat canola oil over medium-high heat.
Sear lamb on all sides, until deep brown, Remove from pot and set aside.
Add butter and flour to pot and stir to combine until you have a paste (roux). Cook for 2 - 3 minutes, (then deglaze with wine or stout, if using) and add onion and carrots.
Season with salt and pepper and stir to coat vegetables with roux (butter and flour mixture). Cook for 6 - 8 minutes, until onions begin to soften.
Add potatoes, peas, thyme, bay leaves, and stock to the Dutch oven. Return lamb and it's juices to the pot. Stir to combine and cover.
Reduce heat to low and gently simmer for one hour. Stir occasionally, scraping the bottom of the pot to make sure nothing sticks. (DO NOT BOIL - keep an eye on your pot, adjust the lid slightly if it begins to boil, or reduce heat).
Remove from heat, garnish with fresh chopped parsley and serve.