Eggs – How to make a Paleo yogurt-based frozen custard

You can do it sans machine, but you are limited to small batches, and it tends to form crystals. You have two choices, bags or freezer container. Bags tends to make less crystallized product, and is a bit faster.

Bags

Get a large 1 gallon ziploc bag, lots of ice, a ~2 cups salt, a small, 1 quart bag and the mix to be turned into ice cream (or frozen yogurt). Chill the mix in the fridge beforehand. This helps the mix cool more quickly and evenly, meaning smaller crystals, meaning creamier product.

Place the cream mix in the small bag, and leave a bit of air. Make sure it is sealed well, you may want to double bag it. Put the small bag in the big bag.

Fill the big bag about half way with ice and add a few tablespoons of salt. Seal the big bag and start mushing the small bag from outside the big bag, moving it around and getting it in contact with the ice. You probably want gloves or to wrap it in a towel: it gets really cold. After the ice melts down, add more ice and salt, keep squishing until the stuff in the bag gets hard. You can toss it on the floor and squish it with your feet while watching TV or reading. Put it in the freezer for a few hours to condition.

This isn't quite as nice as a machine. To compensate for the extra crystallization, you can add more fat and sugar, since those stop large crystals from forming. With frozen yogurt, I don't think there is much you can do.

Freezer Container

This is easier, but makes lower quality product. Simply put your mix in a large container (leave at least half empty), and place in the freezer. Take it out every 10 minutes and shake vigorously for a few seconds. Repeat until it won't move anymore. Use a fork to fluff the mix.

Custard should taste eggy. This is a feature, not a bug. However, from your mention of flour, I think what you're talking about is a souffle, not something like a creme brulee or along those lines. Would that be correct?

Edited based on subsequent clarifications:

Ah. Your method is sorely lacking, and your ingredients are off. You need to temper the yolks first, you need to use yolks only, and use cream instead of milk. Here is a smaller version of what I use at work for creme brulee: - 1L 35% cream - 11 egg yolks - 1C sugar - 1 vanilla bean, scraped

Bring cream to a simmer with the vanilla seeds and pod (you can use approx 1.5tsp vanilla extract, pure not artificial, instead). While it is heating, beat the yolks and sugar together until just incorporated. Pour the cream into the eggs whisking briskly to prevent curdling. Pour mixture through a fine chinois. Skim off foam, pour into ramekins. Place ramekins in a pan, add water to 1/2way up the sides. Cover pan with foil. Bake at 275 (convection) or 325 (non convection) for approx 40 minutes, until wobbly in the centre but set. Chill until set, eat.

The deflation is caused by a souffle effect coming from including the egg whites, which are never used in a custard--custards, creme anglaise, etc, are always yolks only. When you include the whites, air will be trapped inside temporarily, and will escape/collapse when the mixture cools. If you bake until fully stiff with my method, you will get hard and rubbery custard by the time it is set in the fridge.

Also, save the whites--they freeze well--for meringues or souffles.