Make 'extra light' béchamel sauce with 1 added ingredient for creamier lasagna

No lasagna is complete without generous layers of béchamel sauce, and ready-made versions are easy to find on supermarket shelves. You can't go wrong with jars of sauces to make up the various layers of a meaty lasagna, but like many cooking enthusiasts, I much prefer making it all from scratch. It means you can make the topping extra cheesy and layer up a colourful array of vegetables without using beef mince.

While I've fine-tuned the quantities and seasoning for homemade vegetarian lasagna, I consulted my book of "hints, recipes and remedies from a by-gone age" to make the béchamel sauce lighter and creamier. The book "What Our Grandmothers Knew: Hints, Recipes & Remedies of a Bygone Age" was first published in 1979 by The Reader's Digest Association, and it holds some quirky life hacks for every household task, including how to make "extra light béchamel sauce".

The tip reads: "To make an extra light béchamel sauce, stir the white of an egg beaten to a froth into the cream before adding the cream to the mixture".

It was easy enough to try. I separated an egg white from the yolk with great concentration and with some luck, ended up with a pure egg white. Using a whisk, I frothed up the egg white and added it to the 600ml of milk I had measured out to make a white sauce for my lasagna, starting with a roux.

A simple roux is made from equal parts butter and flour, then you must add enough milk to loosen it into a pourable mixture.

At first, it was difficult to see any difference from the white sauce compared to my usual recipe (simply forgo the egg white). But the effects soon became clear after a few minutes of stirring the milk into the roux.

Vegetarian lasagne recipe

Ingredients

For the lasagne:

• Dried lasagne sheets
• Two aubergines
• Two salad tomatoes, sliced into rounds
• Two tins of chopped tomatoes
• One large red onion (or two to three small ones)
• One green pepper (optional)
• Tomato puree/paste
• Good quality extra virgin olive oil
• Oregano or dried Italian herbs
• Balsamic vinegar
• Salt and pepper
• A handful of cheddar cheese
• One ball of mozzarella (optional)

For the béchamel sauce:

• 50g salted butter
• 50g plain flour
• 600ml milk
• Black pepper
• A sprinkling of nutmeg (optional)
• A handful of grated cheese (optional)

Method

For the lasagne:

First, wash the aubergines and pat dry with a clean tea towel. Chop off the very top and bottom of each one to remove the green stalk, and then carefully slice the aubergine into thin strips, lengthways. You can cut them into thin rounds if you prefer, but lengthways makes them easier to layer with the lasagne sheets and sauce when assembling the lasagna.

Lay the aubergine slices on a baking tray lined with greaseproof paper and drizzle them with olive oil. Cook in an oven, or an air fryer at around 180C for 10 to 15 minutes until softened and slightly grilled. Alternatively, pan-fry them with some oil.

If using, slice the pepper up into chunky squares (I use green pepper for colour) and remove the seeds.

Peel and chop the garlic and onions, then add them to a saucepan with olive oil and tomato paste over medium heat. Cook for three minutes before adding the chopped tomatoes and pepper. Rinse the tomato tins out with a little water and add to the pan.

Season with oregano, basil, or Italian herb seasoning, salt, and pepper, plus a dash of balsamic vinegar, then leave to simmer for about 10 to 12 minutes on a low heat.

Set aside while you make the white sauce.

For the béchamel sauce:

Carefully separate the egg from the yolk. Crack the egg over two mugs or ramekins, allowing the white to drip into one of them as you move the yolk between two halves of the egg shell.

Pick out any eggshell that may have fallen into it, then whisk to froth up the egg white.

Measure out the milk in a jug and pour in the thick, frothy egg white. Whisk the milk and egg together to froth everything up a little.

Weigh out the butter and flour, adding the butter to a small saucepan over low heat. When melted, add in the flour and stir continually with a wooden spoon in a figure-eight motion over low heat to make a roux.

In three to five minutes, you'll have a light roux that should puff slightly. Slowly pour in the milk a little at a time while stirring the roux and turn up the heat a little.

It may seem very liquidy for a while until the mixture thickens, but you will soon see the egg white work its magic. The béchamel will be noticeably light but thick and take a creamy white colour.

Add the nutmeg if using and plenty of black pepper for flavour. At the end, I added a handful of grated cheese and stirred it through.

The result? Unlike previous white sauces, this one didn't turn dry or thick in the pan when I took it off the heat. The egg white helped it to retain the silky texture and made for a spreadable, creamy delight, which made for the perfect white sauce.

If you struggle with lumps in the roux, the Reader's Digest book notes: "White sauce will be smoother and less likely to go lumpy if before you add the milk to the mixed flour and melted butter, you stir in enough water a little at a time, to make a stiff cream."

Assembling the lasagna:

Layer some bechamel sauce on the bottom of your lasagna dish, followed by a single layer of lasagna sheets. Top with a generous layer of tomato sauce, followed by a layer of the cooked aubergine slices and top with a generous layer of white sauce.

Repeat as many times as you can until you fill the dish, finishing with a layer of pasta sheets and bechamel sauce. If you wish, top with grated cheddar cheese and torn-up mozzarella. I add a layer of sliced tomatoes for an aesthetic finish.

Cook in a preheated oven set to 180C/ 160C (fan) for 45 minutes. When cooked, leave the lasagna to cool for five minutes before slicing it into portions and garnishing each with a fresh basil leaf.

You should notice the white sauce stays super creamy and doesn't get lost amongst the tomato sauce and pasta, which can happen with a thicker béchamel mixture.