Combine the cornstarch and 50ml whole milk, leave to rest.
Zest the lemon and squeeze the juice enough to make 70ml. Heat the juice with 30gr sugar until syrupy, remove from heat, cool.
In a small saucepan combine 100ml milk, 125ml double cream, 85gr sugar, lemon zest in fine strips, the saffron powder or turmeric (for the color, optional), heat until boiling, remove from heat, let steep for 10min. Strain the mixture, return to the saucepan and heat again until almost boiling, add the cornstarch milk and cook on medium stirring constantly until thickened. Remove from heat and stir in 300gr strained Greek yogurt and the lemon syrup. Cool in the refrigerator overnight.
Freeze in your ice cream maker according to the manufacturer's instructions. Pack into an airtight container, alternating layers of ice cream and as much redcurrant jelly as you'd like (I used 5-7tsp). Pair with fruit and berry sorbets of choice.