Barbacoa Beef Tostadas

I love the ease of a crockpot recipe, but so many of them taste the same to me.  They all just end up tasting like a bland pot roast.  Every once in a while I'll come across a winner, and when I do we usually eat it on repeat.    About a year ago I tried this Barbacoa Beef recipe from Designer Bags and Dirty Diapers and T and I both fell in love.  I've tweaked the recipe a bit, and this week we tried it on tostadas and it was a total hit.  Here's the recipe we used:

Barbacoa Beef Tostadas

For the Beef: 

3 lbs beef for stew (the kind that's already cut into cubes at the store)
4 cloves garlic, minced
2 chipotles in adobo sauce, chopped
1 small white onion, chopped
1 lime, juiced
2 Tbsp apple cider vinegar
3 bay leaves
1 Tbsp ground cumin
1 Tbsp oregano
2 tsp salt
1 tsp pepper
1/2 cup water

Combine all ingredients in a slow cooker and toss until the beef is evenly coated.  Cook on low for 8 hours. Remove the beef from the liquid with a slotted spoon, and shred with two forks.  Add the shredded beef back in to the liquid.  Let it sit in the liquid for an additional 10 or so minutes.

For the Tostadas:

Packaged tostada shells
1 can of refried beans
Shredded lettuce
Mexican shredded cheese
Salsa
Sour Cream (optional)

Warm tostada shells in the oven on 375 for a few minutes until they're shiny. This will crisp them back up if they've gone a little stale.   Meanwhile microwave the refried beans until warm and spreadable, about 1 minute.

Spread 1 Tbsp of beans on each tostada.  Top with shredded beef, cheese, lettuce, salsa, and sour cream.