Preheat oven to 350. In large mixing bowl beat milk, peanut butter, egg and vanilla until smooth. Add Bisquick, mix well. Chill at least 1 hr. Shape into 1 in. Balls. Place 2 in. Apart on Pam sprayed cookie sheet. Bake 10 to 12 mins. Or until lightly brown around edges-be careful not to overbake. Immediately press a candy kiss in center of each cookie. Cool on rack until candy kiss sets. Keep stored in air tight container.