Preheat the oven to 375° F. Prepare an 8x8 square baking pan by lightly coating with butter or baking spray and lining with parchment paper.
In the bowl of a food processor, mix together the flour, sugar, baking powder, and salt. Add the butter and pulse until you have course crumbs. Add the egg yolk and vanilla and continue pulsing until the mixture just comes together in a ball.
Press the dough into the baking pan in an even layer. Top with the jam and spread evenly.
Back in the food processor, mix together flour and brown sugar for the crumb topping. Pulse the butter into the mixture until you have coarse crumbs. Add the oats, pecans and cinnamon, and pulse again until just combined. Using your fingers, pinch together the crumbs and sprinkle over the layer of jam.
Bake the bars for about 35 minutes, or until golden brown. Remove from oven and cool for at least 20 minutes before cutting.