Toast the keto bread to make crostini: bake slices at 350ºF until dry and crisp at the edges and beginning to brown, about 15 minutes, flipping half way through.
Slice tomatoes and lay them on a paper towel to absorb excess moisture. Season with salt and pepper.
When bread is toasted, add pesto, top with tomato slices, and finally torn burrata cheese. Serve immediately.