Season the pork shoulder on all sides with taco seasoning. Place in a 6 quart slow cooker. Add the onions, garlic and broth. Cover and cook on HIGH for 4 hours (or low for 6-8 hours) or until very fork tender. Use 2 forks to shred to very small pieces.

Place 1/2 of the shredded pork into a powerful blender. Add 1/2 cup liquid from the slow cooker and 4 tablespoons melted butter. Pulse and puree until you have a smooth pate (you may need to open the top and move the liquid around). Taste and add more taco seasoning and salt if desired.

In a large glass bowl or 9 inch pie plate, spread the pork pate.

Spread the sour cream (or guacamole) on top of the pork.

Place the rest of the shredded pork on top of the sour cream layer.

Layer the salsa on top of the shredded pork, followed by shredded lettuce, cheese, green onion, diced tomato, green onion if desired.