Black Berry Jam Pie - Test 1

Some of the recipes I Frankensteined this one from instructed to separate the eggs and make a meringue with the whites and 3 Tbsps from the sugar. I want to see what it would be like to simplify it and just put in the eggs.
1 - WAY too sweet. The amount of sugar to add, if any, is dependent on the sweetness of the jam, so it has to be to taste, with an explanatory note; I am thinking that making a custard pie should be enough - egg yolks and no egg whites - still not sure about adding a soft meringue on top; the flour is essential or the pie is too wet. Looking forward to trying it with crème fraîche, although I think its tang is very close to that of the buttermilk, making it a great candidate for using up extra buttermilk; I suspect the cooking time is too long, since the crust went in unbaked and came out almost burnt, and the custard itself was quite an unattractive sort of purple-brown.

2 - I tasted the jam and decided to try with no added sugar. Just right! I also beefed up the instructions from "mix everything together and dump into a pie shell". Really quite good! I wonder about trying it with other jams.

1/2 cup butter, melted

1 cup (325g) blackberry jam

1 cup either sour cream, buttermilk, full fat yogurt

1 tsp lemon zest or vanilla

small pinch of salt

4 eggs

pie shell

1. Melt the butter and whisk in the jam to loosen it up.
2. Mix in the yogurt, the lemon zest/vanilla and the salt.
3. Separate one of the eggs and whisk the egg white to use some of it to brush the unbaked pie crust with. 
4. Whisk in the eggs and the remaining white and yolk until well combined.
5. Pour into the unbaked pie shell.
6. Bake at 325F for 45 minutes