First, Make The Raspberry Sauce:

1. Combine. Add raspberries, lemon juice & sugar to a blender. (If using frozen raspberries, remember to at least partially thaw them first, so they’re easier to blend!)
2. Puree until the sauce is as smooth as possible. Pause to scrape down the sides of the blender as needed.
3. Strain out the seeds by pouring the raspberry puree through a fine mesh sieve. Place the sieve over a bowl, then pour the raspberry sauce into the sieve and pressing down using the back of a spoon or a flexible spatula to remove any seeds or large pulp from the sauce. Discard the seeds and pulp, and pour the smooth sauce into a bowl, container or small pitcher.
4. Serve or Store. Store raspberry coulis in the refrigerator up to 1 week, or freeze up to 1 month.

Build a Knickerbocker Glory

1. Check Your Sauce. The raspberry sauce should be easily scoopable straight from the fridge, but if yours is feeling too thick, you can thin it out with a teaspoon of water or two, until you reach your desired consistency. Set out a tall glass for each sundae you plan to make. 
2. Layer raspberry sauce, fresh berries, and a scoop of ice cream in the bottom of each glass. 
3. Repeat layers to fill your glass and top the final ice cream scoop with a little more raspberry sauce.
4. Garnish with whipped cream, and add meringue, coconut rolls, nuts, or a fan cookie, to taste. I like to add a small whole strawberry or a larger strawberry half for garnish, too! Serve with a long spoon and dive in!