Butter and line a 22.5cm x 22.5cm/9 x 9 inch baking pan with non-stick baking paper.
Into bowl of food processor place the flour, ground almonds, sugar and salt.
Pulse just to combine.
Add in the cold chopped butter, vanilla and almond extract (if using).
Process until coarse crumbs are formed. It should look like damp sand.
Press ⅔ of the mixture into you baking pan. Keep the rest of the crumb mixture because this will become your crumble topping.
Spread the jam over the pressed-in pastry in the baking pan.
Sprinkle evenly with the reserved mixture and almonds. It's nice if some of the jam peeks through.
Bake in oven for 40-45 minutes, until lightly browned.
Remove from oven and cool. For easier slicing, cover with plastic wrap and refrigerate for several hours once completely cool.
When cold, cut the bars into squares and drizzle with icing.
Allow the icing to set.
For the glaze
Combine the powdered (icing) sugar, almond extract and milk. Stir to obtain a nice drizzling consistency. Warm in the microwave if to thick in 10 second bursts.
What you need to know
If you don't have food processor, just rub the butter into the flour mixture with your fingertips until you obtain coarse crumbs.
Have the jam at room temperature.
Refrigerate bars to make it easier to cut
Sift the powdered/icing sugar otherwise the glaze will be lumpy
What is a 'drizzling consistency"?You can test this by taking a spoonful of the glaze and allowing it to drizzle back into the bowl. It should leave a trail. If it's too thin, adjust by adding more powdered/icing sugar. If it's too thick, add a little more milk drop by drop.This recipe has been adapted from Baking and Boys.