Miscellaneous with capers

1 tablespoon olive oil , plus extra for brushing 2 tablespoons onions , chopped 2 garlic cloves , crushed 400 ml tomato passata or 400 ml canned chopped[...]

2 tablespoons scallions , minced 3/4 teaspoon fresh dill , minced 1 teaspoon skim milk 4 ounces bagels , split 2 plum tomatoes , thinly sliced 4 1/2 ounces[...]