Decide what you need: thick spread (use strained Greek yogurt or labneh) or a creamy filling (use sour cream, blended ricotta, or loosened cream cheese).
Start with the listed ratio; if the substitute is looser than fromage blanc, drain/strain 20–30 minutes before using.
If your substitute is thicker than fromage blanc, loosen gradually with 1–2 teaspoon milk per cup until the texture matches your dish.
Taste and rebalance: add a pinch of salt for dairy depth, or add a tiny splash of lemon juice to sharpen tang if needed.
For baking, mix until smooth (especially with ricotta) to avoid graininess in cheesecake-style textures.