To make the cookies, beat the sugar and butter together in a bowl, with a hand mixer, till smooth and fluffy. Add the milk and vanilla and beat until combined. Set aside.
In another bowl bowl, sift together the flours, baking powder and salt. Add this to the wet ingredients in batches, and mix well by hand till combined. If the dough isnu2019t quite coming together, add a tsp or so of milk and knead. Do not be tempted to add too much milk or knead more than necessary to bring the dough into a ball which can be rolled out, as you cookies will become tough.
Roll the dough out uniformly till just about 1/4" thick. Cut out cookies and place them on ungreased cookie sheets. You can place them quite close to each other as the cookies will not spread out or puff up much.
Bake them at 180C (350F) for 10 to 20 minutes, depending on the size and thickness of your cookies. When done the cookies must still be pale and just beginning to turn golden at the edges. Let them cool on the tray for about 5 minutes and then cool completely on a rack.
Store them in an airtight container till ready to decorate. I stored mine for 10 days before I decorated them. Humidity can soften these cookies, and you can just warm them in the oven or microwave to crisp them before decorating. Make sure they are cool. This recipe makes quite a few cookies, depending on size and shape.
For the Egg Free Royal Icing, you can double this quantity if you need more icing.
Sift the sugar and cornstarch together and put it into a bowl. Add the the lemon juice and the milk, 1 tsp at a time, until the mixture becomes a smooth, but thick paste.
Divide the icing into different bowls according to the colours you need. Add a few drops of required colour to each bowl and mix till you get the shade you want. Keep for about 10 minutes till all the air bubbles come to the top.
You can adjust the consistency of this icing according to your requirement. If you need to thin the icing add a bit of milk/ water and mix till you get the desired consistency. If you need it thicker, add more icing sugar as required.
The icing will harden if left open so put it into your piping bags and keep ready for use. Using couplers with your icing bags is good as it is easy to change the tips. If you do not have icing tips or couplers, you can still using a piping bag or a ziplock bag and just make sure you cut very little off the tip so you can get fine lines for decorating.
Decorating The Sugar Cookies : Keep all your icing, tips, cookies, toothpicks/ wooden skewers and whatever else you need at your work table. Spread your work table with some old newspaper or something similar to make cleaning up after easier. I know this is basic stuff, but just thought Iu2019d mention it.
You can either start decorating you cookie directly like I did my orange flowers on the square cookies. Otherwise you can pipe a base layer on your cookie.
There are many different ways of piping and working the icing depending on what pattern or design you are aiming for.
You can also have two sets of icing (a thicker one for outlining and a thinner one for flooding) of the same colour. Otherwise you can use the same to do both like I did.
First outline the area that needs to be filled with colour. If you want the outline to show up distinctly, then wait till it is completely dry. Then fill the space with the colour.
If you are working with different colours, you would need to let each one dry before using the next colour to prevent the colours bleeding into each other. For detailed instructions on decorating using icing, please see the challenge recipe.