Jam Tarts - Lemon JAM recipe

[LimeSlice]

You are looking for a marmalade recipe that yields a firm gel, but you are going to want to strain it, you need to not have the rind/chunks in there.
I dare say you won't get that bright, bakery-fake yellow though, not if you stick to wholly *natural* ingredients...

ETA: try this Lime marmalade recipe | Dan Lepard | Life and style | The Guardian, but replace the lime for lemon.

[Rivlas]

Have you thought about using lemon butter instead. My DH makes this and we use it for all sort of things. It is thick and tangy and very yummy

[Tinks]

That lemon jam stuff in the bakery lemon tarts is bought, it probably doesn't contain any lemon. I'd say look for a lemon butter or lemon spread recipe. Or buy a jar of Kraft (eta) Lemon Spread or even try a lemon meringue pie filling.