Choose a substitute based on texture: use the thickest jam/preserves first; only use thickeners if your jar is pourable.
Start with the listed ratio (most swaps are 1:1). If adding a squeeze of citrus, add a few drops at a time so you don’t thin the paste.
For baking or glazing, gently warm the substitute 20–40 seconds so it spreads evenly, then stir until glossy.
If the substitute doesn’t feel “sliceable,” simmer it 5–10 minutes to reduce, or thicken with a cornstarch slurry in small increments.
Taste and adjust: add a pinch of salt to boost fruit flavor or a tiny bit more citrus for a guava-like tang.