Heat milk and all spices on med. heat ( do not boil) Reduce heat and simmer Sauté onion and 1 tablespoon butter until translucent about 8 minute.
Add to milk mixture.
Melt remaining butter and add flour, making a roux , about 3-4 minutes. Add to milk mixture on low heat Add cheese, except 1/2 cup Montery Jack for topping. Keep on very low heat careful not to burn, stir until melted Remove from heat and cool 15 minutes Drain artichokes and cut into small pieces Add spinach and artichokes to mixture and blend well.
Finally, add lump crab with large spoon. Fold in gently.
Pour into 11x9x2 casserole pan and top with remaining Monterey jack cheese. Bake at 350°F 12-15 minutes.
Serve with tortilla chips warmed in the oven and pico de gallo!