Preheat the oven to 350F Line a 9x9 square baking pan with foil or parchment paper with long ends so you can lift the bars out after they've cooled for easy cutting.

Cream the soft butter, sugar, and cardamom until light and fluffy, about 3-4 minutes, scraping down the sides of the bowl as necessary. Beat in the vanilla and salt. Note: it's important that your butter be at room temperature. I like to leave it out overnight when I know I'll be baking.

With the mixer on low, slowly add the flour and mix just until there is no dry flour left. Don't over mix.

Take 2/3 of the dough and pat it into the bottom of your pan. I like to scatter the dough in crumbles across the bottom, and then start to pat it down. It helps to flour your fingers, or use the bottom of a metal measuring cup to tamp it down. Take the time to get the dough evenly distributed. Note: you're not looking to go up the sides of the pan with the dough, just to make an even flat layer. Steal a little more dough if you need it to cover the bottom. I like to refrigerate the pan and the remaining dough while I make the filling, just to keep it chilled.

Toss the fruit with the sugar, extract, and lemon and mix well.

Spoon onto the crust, spreading out evenly. Top with the remaining dough, making crumbles with you fingers as you add it. Some of the fruit will show through, that's not a problem.

Bake for 30 minutes or until just starting to turn golden and the fruit is sizzling. Let cool before lifting the crumble out and slicing into bars. Sprinkle with powdered sugar just before serving.