In the work bowl of a food processor, pulse together olives and oil until coarsely chopped. Using a rubber spatula, scrape sides of bowl. Add goat cheese, rosemary, and pepper, pulsing just until combined.
Using a small offset spatula, spread 1 tablespoon olive mixture onto 8 frozen white bread slices and 8 frozen wheat bread slices. Stack a wheat bread slice on top of an olive spread-covered white bread slice. Cover with remaining frozen white bread slices to make 8 triple-stack sandwiches.
Using a long, serrated knife in a gentle sawing motion, trim and discard crusts from sandwiches. Cut each sandwich into 2 (approximately 3×1-inch) rectangles. Cover with damp paper towels, and let thaw before serving.
Garnish with rosemary, if desired.
Notes
Olive and goat cheese spread can be made a day in advance, stored in an airtight container, and refrigerated. Let come to room temperature before using. Sandwiches can be made several hours ahead, covered with damp paper towels, placed in an airtight container, and refrigerated. Let come to room temperature before serving.
Recipe by TeaTime Magazine at https://teatimemagazine.com/olive-goat-cheese-tea-sandwiches/