I have been baking a lot of macarons lately. What a sweet obsession! O(∩_∩)O~
Different fillings bring different textures and flavors to macarons. And I have been experimenting all sorts of different fillings. Because macaron cookies are very sweet, I like macaron fillings to be moist, not too dry nor wet; mild, not too sweet nor greasy. After lemon custard, I make apricot filling which is also very tasty and refreshing.
Add lemon juice and pectin. Keep cooking and stirring until the sauce thickens up to coat the back of a wooden spoon. Remove from heat and allow it to cool down.
After the sauce is cooled down, spoon a couple teaspoons of filling between every two macaron cookies.
Cover with plastic wrap or store in an air-tight container. Refrigerate overnight to maximize their texture and flavors.