Place pineapple, chile sauce, soy sauce, and crushed red pepper in a crock pot. Mix well.
Season beef with 1/8 teaspoon salt and 1/8 teaspoon pepper and add to the crock pot. Add onion and stir to coat.
Cover and cook on high for 3 to 4 hours or on low for 7 to 8 hours.
Season with additional crushed red pepper, if desired and serve with tomatoes, if using. Serve with excess sauce and toothpicks. Yum!
Alternatively, recipe can be baked in the oven, covered, at 325 degrees F for 3 to 4 hours.
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