Heat oven to 350 degrees. In small, shallow bowl, whisk egg. Cut goat cheese into 12½-inch rounds or roll into 12 equal balls and flatten. Dip each round into egg mixture and then roll in pecans, pressing them into cheese, if necessary.
Place rounds onto sheet pan and bake 10 minutes, or saute in pan over medium-high heat, about 5 minutes per side. Remove from oven or pan and allow to cool slightly.
In sauté pan over medium heat, cook onion in oil with ground cinnamon and granular sugar substitute, about 3 minutes. Add 6 ounces of blackberries and smash each with a fork. Cook 3–4 minutes, then add balsamic vinegar and season with salt and black pepper.
Cook another 2 minutes, remove from heat and allow to cool. Dressing can be used warm or cooled further. Add lemon juice or water if thinner consistency
Combine spinach, tomatoes and remaining blackberries. Toss with half of the dressing then place goat cheese medallions on top. Serve with remaining dressing on the side.