Preheat the oven to 350 F (175 C). Line an 8"x8" pan with a piece of parchment paper.
In a large mixing bowl, mix together the flour, oats, granulated sugar, brown sugar, cinnamon, baking soda and salt until everything is evenly combined.
2 cups (250 grams) flour, 2 cups (180 grams) rolled oats, 1/2 cup (100 grams) granulated sugar, 1/2 cup (100 grams) light brown sugar, 1 teaspoon cinnamon, 1/2 teaspoon baking soda, 1/2 teaspoon salt
Cut the butter into small cubes and add it to the dry mixture. Using your fingers, work the butter into the mixture until fully incorporated and the dough starts coming together when squeezed.
1 cup (225 grams) unsalted butter
Once it starts forming clumps, drizzle the vanilla extract over the dough. Use your hands or a spoon to work it into a dough. It’s going to look like way too much for an 8”x8” pan, but I promise it’s correct.
1 teaspoon vanilla extract
Scoop about 2/3 of the dough (roughly 582 grams or 2 2/3 cups) into the prepared pan. Press it firmly and evenly into the bottom to form the crust.
Mix together all the filling ingredients in a small bowl. You do this now so that the raspberries don't thaw.
2 1/2 cups (355 grams) fresh or frozen raspberries, 7 tablespoons (125 grams) raspberry jam, 1/2 teaspoon vanilla extract, pinch of salt
Spread the raspberry filling over the crust, leaving a small border of about 1/3" around the edges (this will prevent the jam from leaking out the sides).
Sprinkle the remaining crumble mixture evenly over the top of the jam. Lightly press the topping into the jam without flattening it too much. This is to ensure that no pointy oat bits burn.
Bake for 30-40 or until the top is golden brown and slightly puffed, and the jam is bubbling around the edges. Remove to a cooling rack and let the bars cool completely in the pan, about 2 hours. Then chill for at least 2-3 hours or overnight before cutting.
Store the bars in an airtight container in the fridge for up to 5 days. To freeze, slice into squares and freeze in a single layer before transferring to a freezer-safe container. They’ll be good for up to 3 months. Thaw overnight in the fridge before serving or let them sit on the counter for about an hour.