We're stumped so we thought we'd come and ask the experts.
Last weekend we were in Paris, and bought what we think was normal unsalted butter (from a marche franprix) and (again as far as we are aware) normal garlic.
We melted the butter on a low heat, cut up 2/3 cloves of garlic, put them in the butter, left it to simmer for 3/4 mins and out came lovely tasting Garlic butter with a strong (but not overpowering) Garlic flavour, almost slightly salty - very similar to Pizza Express Garlic butter if you have ever had that.
We fell in love with the stuff so as soon as we got home bought some garlic and unsalted butter from a UK supermarket. Worked through the same process and it was naff.
There's no strong garlic flavor, the butter looks very yellow and has a strong buttery flavour.
Does anyone know why there would be such a difference? A quick google shows no difference between French & English garlic or butter.
P.s. in Paris we repeated the process 3/4 times so it wasn't a one off fluke