• Preheat the oven to 145 degrees Celsius / 295 Fahrenheit. 
• Prepare and weigh out the ingredients, separating the egg whites from egg yolks if necessary. 
• Sieve the ground almonds and powdered sugar and then blend together until they are a very fine consistency and completely combined. 

Italian meringue

• Place the water and granulated sugar into a saucepan. Gently warm the water and stir to dissolve the sugar. Once it has dissolved, turn up the heat, stop stirring and place the sugar thermometer into the mixture. 
• Once the thermometer starts to climb above 105 degrees Celsius/220 degrees Fahrenheit, whisk the egg whites until they form soft peaks.
• When the sugar syrup reaches a soft boil temperature of 115 degrees Celsius/240 degrees, start whisking the egg whites again and pour in the sugar syrup a little at a time. 
• The Italian meringue will turn a smooth, glossy and opaque white. Continue to whisk once all of the sugar syrup has been added to bring down the heat until you can touch the side of the bowl and it feels warm but not hot. 

Almond paste

• Make the almond paste by mixing the remaining egg white with the ground almond/powdered sugar mixture until it is fully incorporated. If using food colouring, add it at this point. A half teaspoon should be sufficient depending on how intense you want the colour.

Macaronage

• Now mix the Italian meringue into the almond paste in three stages. 
• Firmly mix in the first third of the Italian meringue with a metal or wooden spoon to loosen the almond paste and fully combine the two mixtures. 
• Fold in the remaining two thirds one at a time using the softer spoon or spatula, being very gentle with the final third to not overmix the batter and make it too slack. 

Piping macarons

• Move the macaron batter to a piping bag. Tie a knot in the end and relax the mixture slightly in the bag with your hands for a few seconds. Cut half a centimetre from the tip of the piping bag. 
• Position the piping bag perpendicular to the tray with the nozzle a few millimetres above the surface. Squeeze the bag without lifting it up for two or three seconds, then stop squeezing and make a little circle to twist it off. Fill the trays leaving a 2cm gap in between each macaron. 
• Firmly smack it down onto the work surface twice to settle the Italian macaron batter and get rid of any air bubbles. 
• Bake straight away for 17 minutes, then remove from the oven and allow the macarons to cool on the tray. This is a no-rest macaron recipe, but if you cannot fit all of your macarons in the oven at once, it won't harm the remaining macarons to be out on the worktop for 17 minutes. 

Lemon cream filling

• Mix the yoghurt and mascarpone together and grate in the lemon zest. 
• Whip the cream until thickened and then fold in the lemon mascarpone yoghurt mixture. 
• Put the filling into a piping bag and pipe a circle in the centre of each macaron shell. Then pipe a circle around it before sandwiching with another macaron shell.