Spread 1/2 tablespoon of peanut butter on each slice in a thin, even layer. Top 4 of the bread slices with the other 4 slices, sandwiching the peanut butter in the middle.
Whisk together the eggs, milk, sweetener, vanilla extract, and cinnamon in a shallow dish.
Heat a large skillet or griddle pan, over medium to medium low heat and spray with cooking spray. Dip both sides of the stuffed french toast in the egg mixture and place in preheated skillet. Cook 1-3 minutes, then flip the french toast and cook another 1-3 minutes on the other side, or until each side is golden brown. Cut french toast in half if desired and top with strawberries if desired!