How to Make It
Sauté onion in hot oil in a medium skillet over medium-high 4 minutes or until tender. Add garlic; sauté 1 minute. Transfer to a bowl; cool slightly.
Add 1/2 cup sun-dried tomatoes, beef, and next 7 ingredients to bowl; combine gently with hands. Shape mixture into an 8- x 4-inch loaf. Cut a 10- x 16-inch rectangle of parchment paper. Place loaf in center of parchment paper to create a sling. Pour 1/2 cup water into bottom of a 5- or 6-quart oval slow cooker. Arrange onion slices side by side in center of slow cooker; lower meatloaf onto onions using parchment as handles.
Place remaining sun-dried tomatoes and ketchup in a miniature food processor; process until well blended and sun-dried tomatoes are finely chopped. Spread mixture over meatloaf. Cover and cook on LOW for 4 hours or until a meat thermometer registers 160°. Lift loaf from slow cooker, using parchment sides as handles and draining any liquid into slow cooker. Let stand 10 minutes before serving.