Preheat the oven to 300ºF. Set a 9x5-inch loaf pan inside a 9x13-inch baking dish. Bring a large pot of water to a boil and keep hot.

Add the allulose to a small, light colored pan (light color so that you will be able to see the color change). Add a few tablespoons of water and heat over medium high heat without stirring. The allulose will melt. Simmer the mixture until it turns a deep golden and almost reddish brown. Add a tablespoon or two of room temperature water to stop the cooking and keep the caramel fluid. Remove from heat and without cooling it, pour into a 9x5-inch loaf pan. Swirl the pan to ensure the bottom is evenly coated. Set aside to cool. Do not try to scoop any of the remaining caramel from the small cooking pot. Instead, place it in the sink and fill with water for ease of cleaning later.

Combine the eggs, yolks, cream, almond beverage, monk fruit, vanilla, and salt in a large bowl. Using an immersion blender (be sure the head of the blender is completely covered by liquid), blend on low until completely smooth. Alternatively, whisk the eggs and yolks together first and then whisk in remaining ingredients.

Pour the egg mixture onto the cooled caramel. If you have used a whisk and not the blender, strain the mixture as you pour it in to ensure a smooth texture. Cover the 9x5-inch loaf pan tightly with foil and place it into the 9x13-inch baking dish. Transfer to the oven and pour the boiling water into the 9x13-inch dish until it comes 2/3 of the way up the side of the 9x5-inch pan. Bake until the custard is set - it should just jiggle when shaken gently and will measure 180ºF, about 1 hour to 1 hour 25 minutes.

When cooked, remove from the oven and remove foil. Set aside to cool still in the hot water bath until cooled to room temperature. Once completely cool, remove the loaf pan from the water and cover the top with plastic wrap. Refrigerate overnight (and up to 3 days).

To serve the flan, run a thin knife around the edge of the pan. Cover the loaf pan with an inverted serving plate (be sure to use a rimmed plate to catch any liquid) then gently invert both the plate and loaf pan to turn the flan out. Slowly lift the loaf pan, leaving the flan on top of the plate. Spoon any remaining caramel out of the bottom of the pan and onto the top of the flan. Serve in slices.