Method
1. Pre-heat oven - 170°C
2. Grease a a clean springform pan with unsalted butter
3. Add rhubarb, strawberries, cornstarch, granulated sugar and lemon to a clean medium bowl
4. Mix briefly
5. Transfer fruit to springform pan
6. Add unsalted butter and granulated sugar to a clean stand mixer bowl
7. Cream until light and fluffy
8. Add vanilla extract to the batter and continue mixing
9. Mix in eggs to the batter one by one
10. Add all purpose flour, ground almonds and baking powder to the batter
11. Mix briefly until just combined
12. Transfer batter to springform pan
13. Bake until springy to touch - 45 min, 170°C
14. Let cool