Make the shells: Put the confectioner sugar, almonds and instant coffee into a food processor and pulse for about 10 seconds until perfectly uniform. Sift into a large bowl. If only a few large bits remain in the sieve you can discard them, or you can add them back to the processor and grind them again.

In a clean, dry bowl whisk the egg whites and the superfine sugar until you get a thick, glossy meringue. With an electric hand whisk this usually takes about 3 minutes. The meringue should have soft peaks so when you lift the whisk out of it, the peaks just holds their shape. Avoid stiff peaks or youll get hollow shells later.

Add the meringue to the dry almond/icing sugar mixture. Stir together gently, patting down the meringue into the dry mixture against the side of the bowl as you go, stopping as soon as most of dry mixture is no longer visible. The mixture will feel a little stiff at this point. Continue to fold and pat the mixture together gently until the mixture starts to loosen up. This macaronage stage is a critical part of the process and you dont want to over-loosen the mixture so that it feels too runny and at all liquid. To test it is ready, lift up the spatula and let some of the mixture on the spatula drops back into the bowl, leaving a trail or ribbon on the surface. This trail should gently merge back into the mixture, disappearing within about 30 seconds. Pour the mixture into a piping back fitted with a round tip maximum 1/2 inch in diameter.

Pipe macarons onto Silpat or parchment paper, aiming at similar sizes. Lift each baking sheet a few inches off the work surface and drop this flat onto the work surface several times, keeping the tin as flat as possible as you drop it. Leave the macarons to rest at room temperature for about an hour or so, until a very thin skin forms on the surface and the surface does not stick to your finger. During this time preheat the oven to 300 F.

Bake the macarons for about 12-14 minutes, depending on the size, turning the trays around after 7 minutes. Remove from the oven and leave to cool for a few minutes on the trays before carefully lifting them to a rack for matching and filling when completely cool.

Make the filling: To make the filling, start by making the roasted coffee butter (you can make it in advance). Put the butter and the coffee beans in a pan and heat gently until the butter has melted. Bring to a simmer and let the mixture simmer very gently for about a minute. Remove from the heat and leave to infuse for about 30 minutes. Strain it through a fine sieve into a bowl and press as much butter out of the sieve as you can. Refrigerate until set and use what you need in a recipe. You will have some of the grounds in the bottom of the coffee butter but keep them there. If you want to distribute them more evenly, give the butter a mix when it has started to set.