Heat oil in a large non-stick frying pan over a medium-high heat. Add garlic and sourdough crumbs. Cook, stirring, for about 6 minutes or until golden. Remove from heat.
Meanwhile, preheat oven to 200 degrees C. Cut tops off tomatoes and reserve. Cut a sliver of skin off the bottom so they sit flat. Scoop out tomato flesh and discard or save for another use. Put crumb mixture, haloumi, almonds, thyme and caper in a bowl. Season.
Firmly pack filling into tomatoes. Place tomatoes close together in a small roasting dish and replace tomato tops. Spray with olive oil. Remove for 20 minutes or until the tomatoes are soft. Place on a serving platter. Drizzle with oil and serve.