Fruity spice crumble

Ingredients

• Crumble
• 90 grams butter, chopped, at room temperature
• 1/4 cup brown sugar
• 3/4 cup crushed spiced biscuits (about 8 biscuits)
• 1/2 cup self-raising flour, sifted
• 1/4 cup chopped pecans
• warm custard, to serve
• ice-cream, to serve
• 4 pears, peeled, cored, cut into chunks
• 2 tablespoons water
• 1 bunch rhubarb, trimmed, washed, cut into 3 cm pieces
• 1/3 cup caster sugar (see notes)
• 1 grapefruit, peeled, sliced, seeded