1 teaspoon vegetable oil
1/4 cup chopped onion
2 large sweet onions, chopped
4 cups finely diced celery
6 sheets Spanish bread
1 1/2 cups cherry tomatoes
1 tablespoon yellow mustard
1 tablespoon ketchup
2 teaspoons mustard powder
1 1/2 teaspoons chili powder
Place vegetable oil in a large pot over high heat. Cook onion in oil until tender, but not brown. Stir in celery and onions. Bring to a boil. Cook about 5 minutes, stirring constantly.
Add sliced sweet onions, celery and tomatoes; stir well.
Add ketchup, mustard powder, ketchup, mustard powder, chili powder and tomatoes. Reduce heat to medium-low. Stir over medium heat, decreasing heat as necessary, until mixture reaches desired consistency. Set aside to cool.
Arrange bread slices on the prepared baking sheet. Top each slice with celery mixture, onion greens, celery tomatoes and browning sauce. Spoon into rolls and chill overnight.
Return rolls to the prepared pan. Bake at 350 degrees F (175 degrees C) for 30 minutes. Drain roll of celery mixture and discard. Form rolls into dinner rolls.
Cool rolls in tightly covered plastic bag, refrigerated.