Place carrots and onion into the crock pot.
Place the roast on top.
In a small bowl mix together seasonings and sprinkle over the roast.
Pour in the water and cover with a lid.
Cook on low for 8-10 hours or high for 6-8 hours.
Remove roast, carrots and onions onto a serving dish and reserve 2 1/2 cups of broth.
Heat butter in a medium sauce pan over medium high heat.
Once butter is melted, whisk in flour and continuously stir for 1 minute.
Slowly add in broth and whisk to prevent lumps. The slower you add it the better.
Let it come to a bowl then remove from heat. If you want to thin it out a bit, add in a little more broth.