Crepes: Combine all ingredients in a food processor, bender, or bowl. Mix until you have a smooth thin batter. Cover and let rest 30 minutes.
Heat a 10” (25cm) non-stick skillet or crepe pan over medium heat. Brush pan lightly with oil. Add about ½ cup batter to pan. Swirl batter around pan and pour excess back into bowl so crepe will be very thin.
Cook until bottom browns, 2-3 minutes, and turn crepe over to cook other side. Flip out onto clean tea towel.
Repeat until all batter is used. You should have 10-14 crepes.
The first crepe usually does not come out right. Don’t worry, just toss out the first one and continue on.
Filling: Whip cream in a large bowl until thick and cream holds its shape. Beat in vanilla and zest.
Assembly: Place 1 crepe on cake plate. Spread with a thin layer of whipped cream. Sprinkle with 2 tbsp toffee bits. Repeat until crepes and filling are used up. Cover with plastic wrap and chill for 2 hours or overnight. Sprinkle with icing sugar before serving.