Preheat your oven to 350°F (175°C).
Slice the focaccia bread horizontally to create a top and bottom layer.
In a small bowl, mix the softened cream cheese, garlic powder, and black pepper until well combined.
Spread the cream cheese mixture evenly on the cut sides of the focaccia bread.
Layer the sliced turkey breast on the bottom half of the focaccia.
Add the chopped sun-dried tomatoes, fresh spinach leaves, and sliced red onion on top of the turkey.
Drizzle olive oil over the vegetables for added flavor.
Place the top half of the focaccia on the sandwich and press down gently.
Wrap the sandwich in aluminum foil and place it in the preheated oven for about 10-15 minutes, until warmed through.
Remove from the oven, slice into individual servings, and enjoy!