Custard “concrete” with chocolate and biscuits

A custard so thick with mix-ins that you can turn the cup upside down. A quick vanilla base, with mix-ins of your choice.

The concrete is a speciality of the frozen custard stands of St. Louis: fresh soft custard is blended with pieces of chocolate, biscuits or fruit and is so thick that it’s handed over upside down. The base is vanilla with extract instead of a pod, so there’s no infusing and it needs only a short ageing. The mix-ins aren’t counted in the mix composition — they are in pieces and don’t change the custard’s freezing point.

Type: Frozen custard · Servings: 6 · Difficulty: Moderate

Equipment

Ingredients

  • 450 g whole milk 3.5 %
  • 350 g whipping cream 33 %
  • 25 g skimmed milk powder
  • 120 g egg yolk (6 yolks)
  • 140 g granulated sugar (sucrose)
  • 40 g dextrose (glucose powder)
  • 10 g vanilla extract (2 teaspoons)
  • 60 g dark chocolate 70 % (for topping or folding in at the end, chopped into pieces)
  • 60 g butter biscuits (for topping or folding in at the end, broken up)
  • 40 g peanut butter 100 % (optional, or other mix-ins of your choice)

Making the mix

  1. Heat the milk, cream, milk powder and dextrose until almost boiling.
  2. Whisk the egg yolks with the sugar (or the part of it the recipe specifies) until pale and foamy.
  3. Whisking constantly, pour about a third of the hot milk mixture onto the yolks in a thin stream, then tip everything back into the pan.
  4. Stir over a low heat with a wooden spoon until the custard thickens and reaches 82–84 °C (it coats the spoon and a line drawn with your finger holds). Don’t let it boil, or the yolks will curdle.
  5. Immediately strain the custard through a fine sieve into a bowl set in iced water.
  6. Stir in the vanilla extract. Cool the custard in an ice bath to below 10 °C (about 20 minutes), stirring often, then refrigerate for at least 1 hour — left overnight, the custard will be even smoother.
  7. Chop the mix-ins into pieces the size of a pea to a hazelnut and put them in the freezer. Put a mixing bowl and the serving cups in the freezer too.

Method — Compressor ice cream maker

  1. Switch on the ice cream maker 5–10 minutes ahead. Pour in the chilled base (no higher than the fill line) and churn for 25–35 minutes, until thick and glossy.
  2. Transfer the custard to the frozen mixing bowl and put it in the freezer for 20 minutes to firm up a little.
  3. Add the mix-ins (and a spoonful of peanut butter) and, using a sturdy spoon or spatula, vigorously fold and smear them into the custard until it’s as thick as concrete.
  4. Fill the chilled cups and serve at once.

Frozen custard should contain very little air. Churn only until it is thick and glossy, no longer — a long churn just beats in unnecessary air.

Total time: 2 h 45 min

Method — Freezer-bowl ice cream maker

  1. Fit the frozen bowl, switch on the machine and, with it running, pour in the base (no more than two-thirds full).
  2. Churn for 20–30 minutes, until the custard thickens.
  3. Transfer to the frozen mixing bowl, leave in the freezer for 20 minutes, then work in the mix-ins with a sturdy spoon.
  4. Serve at once in chilled cups.

Freeze the bowl for at least 24 hours beforehand. Don’t add the mix-ins in the machine — thick custard with pieces in it would stall the paddle.

Total time: 2 h 40 min

Method — Ninja CREAMi and similar machines

  1. Divide the chilled mix between CREAMi tubs, filling each no higher than the MAX line (a full batch makes about two standard tubs).
  2. Put the lids on and freeze on a level surface for 24 hours.
  3. Place a tub in the machine and run the Gelato program.
  4. Use a spoon to dig a well about 4 cm wide in the centre, all the way to the bottom, add about 40 g of mix-ins (chocolate, biscuits, a teaspoon of peanut butter) and run the Mix-in program.
  5. If the ice cream is crumbly or powdery, run Re-spin (many users add 1–2 tablespoons of milk first).

Programme: Gelato

Only some models (such as the Deluxe range) have a Gelato program. If yours doesn’t, use the Ice Cream program. A standard tub holds about 470 ml, a Deluxe tub about 700 ml. Don’t fill above the MAX line, and freeze it level — the machine doesn’t handle an uneven block well.

Total time: 26 h 3 min

Stages

Preparation
15 min
Cooking
20 min
Cooling
20 min
Ageing in the fridge
1 h
Churning
30 min
Hardening in the freezer
20 min
Total time
2 h 45 min

Serving and storage

Straight away, in a cold cup with a spoon or a wide straw. Do the “upside-down” test over a plate.

A concrete is for eating immediately. Freeze any leftover base without mix-ins as ordinary custard (within a week).

Tips

  • Favourite combinations: strawberries and butter biscuits (“strawberry shortcake”), banana and chocolate, sour cherries and brownie pieces.
  • Mix-ins must be cold and dry — wet fruit freezes into ice, so pat it dry first and freeze it on a tray.
  • Peanut butter, biscuits and chocolate may contain allergens (peanuts, gluten, milk, soya) — check with your guests.

Sources