Coat a casserole dish with nonstick spray, then cut the keto friendly bread into cubes and arrange them across the dish. Keep the cubes in an even layer so they can absorb the custard at a similar rate.

Whisk the eggs, unsweetened almond milk, sweetener, vanilla extract, and ground cinnamon together in a jug until fully blended, then pour the mixture over the bread. Look for custard reaching throughout the dish, with no untouched dry cluster of bread.

Cover the dish and refrigerate for at least two hours or overnight. As it rests, the bread should look hydrated throughout instead of floating above a pool of liquid.

Heat the oven to 375°F, uncover the casserole, and bake for 25 to 30 minutes. The top should turn golden and the center should hold a gentle, firm jiggle rather than ripple like liquid.

Dust the warm casserole with low carb powdered sweetener before serving. The light coating should soften slightly on the warm surface without disappearing completely.