Slow Cooker Beef Tips and Vegetables

• 2 pounds beef, flank steak, tenderloin, sirloin, stewing beef, thinly sliced, ¼ - ½ inch thick, across the grain or diagonally
• 1 large onion, sliced
• 1 cup beef broth -
• ¾ cup soy sauce
• ¾ cup dry sherry or oyster sauce
• 2 tblsp sesame oil
• ½ cup brown sugar, packed or honey
• 3 tblsp garlic, minced
• 2 tblsp ginger, minced
• ¼ cup cornstarch or potato starch
• ¼ teaspoon salt, more or less to taste
• ¼ teaspoon pepper, more or less to taste
• 1 tblsp dried crushed red pepper flakes, optional, more or less to taste
• 4 cups cooked rice or noodles of your choice
• green onions, thinly sliced or toasted sesame seeds optional for serving

Vegetables (up to 6 cups worth)

• 1 cup peppers, green, yellow or red, cored, sliced
• 2 cups mushrooms, fresh, sliced
• 2 cups broccoli, florets or cut into bite sized pieces
• 2 cups sugar snap peas, trimmed
• 2 cups cauliflower, florets, cut into bite sized pieces optional
• 2 cups carrots, sliced optional