In a large skillet, saute onions and garlic in butter over medium heat until tender and brown. Pour into warm crockpot. Place skillet back on the heat and cook sausage completely breaking it apart as it cooks. Drain off any excess grease and add to crockpot with onions. Stir in corn, chicken broth and spices. Cover and cook in crockpot on high for 4-4 1/2 hours.
Whisk heavy cream and flour together until smooth. {I just threw it into my blender.} Pour this into crockpot mixture to help thicken the chowder. Cook another 30 minutes to 1 hour. Serve hot with oyster crackers and parsley.
*For the corn: I usually cut all the kernels off the cob, then use the back of my knife to scrape out the insides + the milk.