BLUEBERRY PAIN PERDU WITH VANILLA ICE CREAM

3 eggs • 1 egg yolk • 200ml single cream • 2 tbsp caster sugar • 2 tbsp whisky (optional) • 30g salted butter, plus extra for frying • 16 sprigs lemon thyme, leaves picked • 2 tbsp clear honey • 200g blueberries • 8 x 2cm-thick slices brioche • 4 scoops vanilla ice cream