Heat 5 tablespoon sugar and 2 tablespoons of water in a pot on the stove. Allow the sugar to caramelize without stirring (it will seize if you stir, especially once it's started boiling). You want a rich, deep color, but you don't want it burned. For this step, you need real sugar. Sweetener won't caramelize as it should.
Quickly pour this caramel into 6-inch soufflé dish that fits inside your Instant Pot.
Be careful not to get any of it on you and do not lick the spoon! This stuff is hot and sticky and burns if licked (how do I know this?).
In a bowl, whisk together the eggs, milk, sweetener, and vanilla extract. As tempting as it is, don't put in a blender. It gets too frothy.
Strain this mixture on top of your hardened caramel. Cover the dish with aluminum foil.
Place 2 cups of water in your Instant Pot, and place a trivet at the bottom. Set it to VENTING, (you won't be pressure cooking this). Place the dish on the trivet, and set your Instant Pot to sauté for 22 minutes.
The pot will turn itself off or keep warm after 22 minutes. Wait until you can open it safely, and use a toothpick in the center to check for doneness. The center will be jiggly, but the toothpick should come out clean.
Refrigerate for 4-6 hours until well chilled.
When ready to serve, use a knife to loosen the edges, place a plate on top of the dish, and Invert it. Thump the bottom of the dish to help it along if needed. The custard should un-mold really easily.
Do not, do not at all lick the spoon after you create your caramel. That stuff is hot and sticky and it will burn you. Honestly, I make the kid and dog exit the kitchen, so no one trips me as I'm trying to pour it.
Don't stick your finger in it to taste it. I know this sounds obvious, but trust me, remind yourself of this before you start to cook this. The caramel looks so dang yummy, it's easy to forget.
Don't be like me and think you'll just blend this and not whisk it by hand. Mine got so frothy I had to wait for an hour for the bubbles to subside. Your ingredients should be well incorporated, but we're not making a milkshake here, so go easy.
It will not taste good if eaten hot. So plan ahead and chill it. It's well worth it. My dad used to have this with whipped cream on top, and that is never a bad way to go.
If you're having trouble with the caramel, if your sauce is crystalizing, there's likely some issue with the sugar or water content. Try again, but this time once it starts to bubble, DO NOT STIR the sauce. This is what causes it to seize. Rather, just shake the pan about to mix things.
It's tough to make this recipe keto due to the caramel sauce. You can, of course, make it low carb by using sugar for the sauce, but using sweetener in the custard.