Preheat the oven to gas mark 6. Chop the plums in half and remove the stones. In a medium baking dish place the plums, sprinkle with the sugar, lemon juice and zest. Mix so the plums are coated.

In a bowl add the flour, butter and almond. Use your fingers to crumble the butter into the flour until it looks like breadcrumbs. Add the sugar and vanilla essence and mix through.

Sprinkle the crumble mix on top of the plums. Bake in the oven for 25-35 minutes until the top is golden brown.