Rub beef chuck roast with pesto sauce and garlic
Heat skillet to a medium high heat (around 400 degrees) and brown roast on each side for 3-5 minutes
Transfer to slow cooker and continue cooking on low for 8-9 hours until fall-apart tender
Preheat oven to 425 degrees
Cut tomatoes in half and toss with olive oil, garlic and salt
Place on baking sheet and roast for 30-35 minutes
Strain juice from slow cooker into sauce pan
Whisk in cornstarch slurry and bring to a boil for 3-5 minutes until thickened
Remove from heat and stir in mustard and sour cream
Serve with rice (I recommend basmati) or as desired