Preheat the oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper.

In a large bowl, mix flour, rolled oats, granulated sugar, and salt, then cut in chilled butter and vanilla extract until the mixture forms coarse crumbs.

Press two-thirds of the crumb mixture into the bottom of the prepared pan to form a firm base.

Spread raspberry preserves evenly over the base, then sprinkle dark chocolate chips on top.

Crumble the remaining oat mixture over the chocolate and raspberry layer.

Bake for 30-35 minutes until the top is golden brown, then cool completely before cutting into bars.