Grilled Steak Skewers with Chimichurri

Ingredients

• 1/3 c. Fresh basil -
• 1/3 c. fresh cilantro -
• 1/3 c. fresh parsley -
• 1 tbsp. red wine vinegar -
• Juice of 1/2 lemon -
• 1 garlic clove, minced -
• 1 shallot, minced -
• 1/2 tsp. crushed red pepper flakes -
• 1/2 c. extra-virgin olive oil, divided -
• Kosher salt -
• Freshly ground black pepper -
• 1 red onion, cut into 1 1/2" chunks -
• 1 red pepper, cut into 1 1/2" pieces -
• 1 orange pepper, cut into 1 1/2" pieces -
• 1 yellow pepper, cut into 1 1/2" pieces -
• 1 1/2 lb. sirloin steak, fat trimmed and cut into 1 1/2" chunks -