Oven 160° and line a square 8” tin with baking paper
1tsp bicarb, 1 tsp Baking powder, 150g sugar (I use light brown) 110g plain flour, 110g oats, 110g butter
Melt the butter in the microwave until just melted, and add the other ingredients and mix until combined. Tip it into the tin and firm it down nice and flat. Sprinkle the berries - fresh or frozen, on the top, spaced out ideally. Then just bake it. It takes 25-30 mins, but until it’s nice and golden.
You can use jam on it, but if I’m doing that I keep a third of mix back to sprinkle on the top before baking. Makes a good date slice that way too, 225g well chopped dates simmered with 125ml water until soft, then add a tsp vanilla extract. Put that on like the jam when it’s cooled a bit, and sprinkle the remaining third on the top.