Clean, wash and cut the rhubarb into pieces of about 1.5 cm. Lightly scratch the skin of the peaches. Scald with boiling water, rinse cold and peel skin. Halve the peaches, stone them and cut them into slices. Melt the fat in a saucepan and let it cool down.
Mix flour, sugar, baking powder and salt in a bowl. Add eggs and fat. First knead into crumbles with the dough hooks of the hand mixer, then with your hands. Put 2/3 of the crumbles into the greased fat pan of the oven (approx. 32 x 39 cm) and press to a smooth base. Stir the jam until smooth. Spread about 3/4 of the jam on the base. Spread rhubarb and peaches on top. Add the remaining crumbles and jam in blobs. Bake in the preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) on the bottom shelf for 35-40 minutes.
Spread about 3/4 of the jam on the base. Spread rhubarb and peaches on top. Add the remaining crumbles and jam in blobs. Bake in the preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) on the bottom shelf for 35-40 minutes. Let them cool down. Whipped cream tastes good with it