Gather the measured ingredients and arrange the brioche slices beside a mixing bowl or shallow soup plate. Slightly older, firm bread is easier to handle than a very soft fresh loaf.

Beat the eggs, then whisk in the heavy cream, brown sugar substitute, and cinnamon. The coating should look evenly blended, with no visible strands of egg white.

Lower one slice into the custard for about half a second, turning it briefly several times to coat both faces. The surface should be moist while the slice still holds its shape.

Heat the skillet and add butter or olive oil, allowing the cooking fat to become hot before adding the bread. Butter should bubble without smoking or developing a sharp, burned smell.

Set the coated slice in the skillet over medium heat, using a fork to guide it, then briefly coat and add the next slice. A gentle sizzle should begin when the bread touches the pan.

Cook for about 1 to 2 minutes before turning, finish the second side, and transfer the toast to a plate for immediate serving. Look for golden surfaces and a set center rather than a wet, loose coating, adjusting the final browning to your preference.