Wash the lemon thoroughly and zest the peel.
Cut the lemon in half and squeeze out the juice.
In a small saucepan, add heavy cream, lemon zest, and lemon juice, then heat gently over low heat.
Finely chop the white chocolate and place it in a bowl.
Pour the warmed cream over the chocolate and let it sit for 1-2 minutes.
Stir gently with a spatula until completely combined and smooth.
Let the ganache cool, then refrigerate for 1-2 hours until set.