Preheat the oven to 350°F. Line a 9-inch square baking pan with parchment paper then cut off any long edges.
Place the butter and sugar in the bowl of an electric mixer fitted with the paddle attachment, and mix together on medium speed until light and fluffy. Scrape down the sides of the bowl with a spatula and add in the two extracts, then mix again until combined. Add in the flour and mix on low speed until the dough comes together into a soft ball, scraping the sides as necessary.
Press approximately 2/3 of the dough into the prepared baking pan, making an even layer of shortbread. Spread evenly with the jam. Add the rolled oats and almonds to the remaining dough in the mixing bowl, and use your hands to mix together to make a crumbly oat- and almond-studded topping. Sprinkle over the jam, leaving some small spots for the jam to peek through for a pretty effect, and lightly press down into the jam. Transfer the pan to the oven and bake for 45 to 50 minutes, until lightly browned and bubbling.
Allow to cool completely in the pan. When cool, use the parchment to lift out of the pan, then cut into bars. Dust with powdered sugar before serving.
Store the bars in a covered container at room temperature for up to a week, or freeze for up to 3 months.