1. Line a 9-inch (23cm) square pan with aluminum foil then butter the insides or spray with cooking spray.
(In the original recipe, the authors said to grease the pan then line it with parchment paper, leaving an overhang on two sides of the pan.)
2. Make the rosemary dough by creaming the butter with the powdered sugar and salt in the bowl of a stand mixer, or by hand, until it’s light and fluffy. Add the vanilla, lemon zest, and rosemary, then gradually add in the 1 3/4 cup (250g) flour, mixing until the dough is smooth.
3. Transfer the dough to the prepared baking pan and pat it flat into the bottom of the pan using lightly floured hands. Refrigerate the dough-lined pan for at least 30 minutes.
(No need to wash the mixer bowl; you can use it as is for the crumb topping in step #7.)
4. Make the apricot filling by combining the apricots, water (or wine), granulated sugar, honey, brandy, and a pinch of salt in a medium saucepan. Simmer over low heat for about 45 minutes, or until all the liquid has just about been absorbed. Let cool for a few minutes, stirring, then puree in a food processor until smooth.
5. Preheat the oven to 350ºF (180ºC).
6. Baked the rosemary shortbread for 25 to 30 minutes, until golden brown. Once baked, let the shortbread cool to room temperature.
7. Make the crumb topping by mixing together the 1/2 cup (70g) flour, brown sugar, nuts, salt, and butter in the bowl of the stand mixer, with the paddle attachment, until the mixture just barely starts clumping together.
8. Spread the apricot filling over the shortbread in the pan evenly, then top with the crumb topping and bake for 20 to 25 minutes, until the topping is browned.
9. Remove from oven and let bars cool completely in pan.
To slice, lift the bars out of the pan by grasping the edges of the foil. Slice into squares.