Place the butter and milk chocolate in a large bowl and microwave in 30-second bursts, stirring together between each interval, until completely melted.

Add the Keto Chow and powdered erythritol and mix until there are no lumps of powder.

Mix in the heavy cream and vanilla extract.

Stir the white chocolate chips into the mixture.

Line an 8 x 4.5 loaf pan with tin foil so that the tin foil hangs over the sides and spray lightly with oil.

Spread the fudge into the loaf pan and smooth with the back of a spoon or spatula.

Chill in the refrigerator for at least four hours, or until the fudge is set and firm enough to cut.

Use the tin foil to lift the fudge out of the pan.

Transfer the fudge to a cutting board and cut into 21 pieces. Fudge should remain refrigerated until serving. It will become soft at room temperature.