As explained in the recipe post, you can either sear your meat or not. If you don't, simply add it to the crockpot. If you do, this is my preferred method, heat your pan over medium-high heat. Add in 1-2 tablespoons canola oil and heat this as well. You want it to be just under smoking point. Add in the beef. Cook for several minutes on one side, then mix and sear on the other sides. If you get a lot of fat released and the beef isn't searing, drain some of the fat and return it to the heat.
Add the beef to your crockpot with the stock, garlic, thyme, bay leaves, and tomato paste. Set to cook on high for 4 hours, you can also do 6 hours on low.
As a reminder, if you cannot cook this in batches, go ahead and add all your veggies in here right now as well. I prefer to add in batches so the vegetables don't get overcooked.
If you did not add in your onions, celery, carrots, and potatoes begin with, add them after the 4 hours (high) or 6 hours (low) are up. Cook for another 2 hours on high, or 3 hours on low.
Add in the frozen peas and let them cook for 10-15 minutes. I like to reset the time for another 4 hours on high, just to keep it heated and going.
Make a cornstarch slurry with the cornstarch and 2 tablespoons of water. Mix it well, then slowly pour it into the beef stew while mixing the stew at the same time. Gently mix this throughout, you don't want to break up the potatoes.
Let this cook another 5-10 minutes until it is thickened. If it doesn't thicken, you may need to pour it into a pan and heat it on the cooktop. Sometimes slow cookers just won't go that high.
If you have to do this, turn it on medium and cook, stirring gently, for about 5 minutes. This should thicken it right up.
Now, sit back and enjoy. You deserve it!