Blueberry jam oat bars

Heat the oven to 350F. Line an eight-inch square baking dish with parchment paper; baking spray optional.

In a large bowl combine 224 g oats, 210 g all-purpose flour, 165 g firmly packed brown sugar, half a tsp cinnamon, half a tsp baking soda and half a tsp salt.

Whisk together, breaking up any brown sugar lumps by hand or with the whisk.

Add one cup melted butter (or browned butter) and stir with a spatula until crumbly and wet.

Reserve one and a half cups of the mixture in a medium bowl for the topping.

Press the remaining mixture into the dish in an even layer with a spatula, measuring cup or clean hands.

Bake the base 10 minutes until fragrant.

Straight out of the oven, spread three quarters of a cup of blueberry jam to the edges while the base is warm.

Variation: raspberry jam with chopped peaches, orange marmalade with diced figs, or guava preserves with chopped strawberries.

Scatter one cup of blueberries over the jam in an even layer.

Break the reserved crumble over the top by hand, leaving some bigger chunks, covering completely.

Bake about 55 minutes until golden, gooey and bubbling.

Cool to room temperature, then chill in the fridge about an hour so it slices more easily.

Cut into pieces, nine for generous portions.

Store in the fridge in an airtight container up to a week, or wrapped tightly in the freezer up to a month.