- Preheat oven to 300F (150C). Line a baking sheet with foil and spray with oil. Slice tomatoes in half. Place cut side up on baking sheet. Bake in centre of preheated oven until tomatoes start to wrinkle and look dry, 40 to 50 minutes. Remove to a rack to cool.
- Cut avocado in half and remove pit. Scoop flesh into a medium bowl. Squeeze in juice from lime. Using a fork, mash until fairly smooth. Finely chop jalapeño. Stir into avocado with sour cream and celery salt until evenly mixed. Use a pointed teaspoon to easily scoop avocado mixture into cups. Top each with a tomato half, then sprinkle with chopped coriander.
This is really just dressed-up guacamole. Instead of a dip, we’ve turned it into stylish, easy-to-eat cocktail bites topped with your own homemade oven-dried tomatoes.
Packages of crispy cocktail cups called “croustades” are sold in many supermarkets, often beside cocktail breads or appetizers. They’ll keep in a cupboard for months.
Roast tomatoes. Cool, then cover and refrigerate up to 2 days. Make avocado mixture up to 5 hours ahead and refrigerate. Up to an hour before serving, fill cups and garnish with tomatoes.