The phrase "large dollop" refers to a significant or generous amount of something. It implies that a good quantity of something is being mentioned or used. Full definition
Put a very large dollop of filling in the shell and place it in the baking dish. (strawberriesforsupper.com)
I didn't have my cake decorating kit with me (it's a long story... I'll tell you about it later) so I got creative and used my cookie dough scoop to place large dollops of the peanut butter frosting around the outer edge. (namelymarly.com)
Add large dollops over the brownie batter. (beautybites.ca)