Making toad in the hole with duck eggs

Toad in the hole batter, which is the same as yorkshire pudding batter, uses eggs for lift and partly as the binding agent. Lift comes from expansion of gases, including water vapor. Egg white is 90% water, yolk is somewhere around 40% water.

A large egg is usually somewhere around 60g out of the shell. With a hen's egg 2/3rd of that is white, so call it 44g of water in total (36 from the white, 8 from the yolk). A duck egg is usually about 1/3 white, so about 34g water in total (18 from the white and 16 from the yolk). So using duck's eggs you get 20g less water overall in a doubled delia recipe. Given that there's 260ml of water and milk already this isn't much of a difference, maybe about 6-7% total water content. This doesn't sound like much but it can make a big difference.

Fat-wise there's about 10g more fat in 2 duck eggs than hen's eggs. A hen egg yolk has roughly 5g of fat in it, and a duck egg double that.

Protein-wise white has a higher percentage of protein (7%) than yolk (5%), but that's not much so not likely to be causing issues.

It's probably the combination of less water and more fat which is causing your problem. Less water and more fat means less expansion, less expansion will mean it takes longer to cook and has a flat texture as you describe.

As for the remedy I think you should definitely try 3 whites and one yolk, that should bring the balance back just right.

One trick recommended by a few chefs is to wait until your toad in the hold or yorkshire batter is fully expanded, then open the oven for a few seconds to let the water-saturated air out. This will help the batter to crisp up.

I have ducks and have been experimenting with making Yorkshire Puddings using their eggs. I always used to use 4 hen eggs, 140g plain flour, 200ml milk + seasoning, and that always worked well. When I substituted the hen eggs with duck eggs they never raised very well. After a little experimenting I found the following works well...

Pre-heat oven to 180deg Put a little olive oil (not extra Virgin) into a Yorkshire pud tray - 12 Yorkshire’s

Mix together.. 2 large duck eggs 90g plain flour 110ml whole milk 50ml water Salt & pepper

Bake for 10 minutes, then open oven door for 2 seconds to release moist air & close again. Then bake for a further 6 minutes.

Done

Hope this works for you. I use an electric fan oven for this.

After further experimentation, I’ve made it work. I used a different recipe, and for each 100g of eggs I used one whole egg and made up the rest of the weight with egg whites (which took a bit less than two more eggs). Leaving the batter in the fridge for twelve hours or more also helped a bit.

In case of link rot, the new recipe uses 200g eggs, 150g flour, 25g water and 175g milk. For the same amount of flour, the Delia Smith recipe that didn’t work so well used two eggs (about 100g), 150g of milk and 110g of water. So the total amount of liquid is quite similar, but there’s more egg and less milk/water.

Duck eggs are high in fat and for a cake to rise it needs to be low in fat or no fat. Try halving one of the duck yolks and see if this makes any difference.