To make the crust, pulse the flour, sugar to combine in your food processor. Then add butter and sour cream and pulse to combine. When the dough has formed a ball, roll it out onto a prepared 10-inch tart pan with a removable bottom. You could certainly use a pie pan for this. Bake for about 10 minutes with foil cover lined with pie weights or dry beans and then 5 minutes without. Let cool while preparing the filling.

To make the filling, peel and thickly slice the peaches. Arrange the peach slices in circles on top of the crust, until it's completely covered. If using 5 or 6 peaches overlap them. Don't worry if your crust looks overfilled with peaches as they will draw up during cooking. Combine the egg yolks, sour cream, sugar, and flour and beat until smooth. Pour the mixture over the peaches.

To make the hearts, drop small circles of puree all over and then take a skewer and drag it through each dot starting with one and ending with the last one, never lifting the skewer until you finish.

Bake for about 1 hour, until the custard sets and is pale golden in color. Transfer the tart pan to a wire rack to cool.