Last weekend, Robbie Lum stayed up for nearly 48 hours and cooked dinner for 100 — broiled California rolls, shrimp cocktail, black bean spareribs, kalua pork, furikake salmon, garlic chicken, tofu salad, namasu, rice, raspberry sherbert cake, dark cherry ice cream dessert, chantilly cake, angel food cake with lemon curd, lime Jell-O dessert.

"People think I'm crazy but I enjoy it," said Lum, 56, whose annual Christmas dinner is her way of saying thank you to friends and relatives for their love and support. It is emphatically NOT a potluck — "the only thing you can bring is your appetite," she tells her guests. She does let her husband make the slow-cooker kalua pork (25 pounds of it this year). And her mother, Thelma Lam, contributes makizushi and potato-mac salad, two of her specialties.

Lum isn't rich and her home isn't a huge palace, but she and her husband, Milton, cram everyone in somehow, with people sitting on the stairs, on the floor, wedged around Milton's pool table, overflowing onto the small lanai.

It was the Christmas ornaments that started it.

Lum began collecting ornaments when her son, Brandon, now a 23-year-old grad student, was a small boy. "I wanted him to remember a beautiful Christmas every year," she said. She'd shop the craft fairs and invest several hundred dollars a year, then spend 20 to 30 hours decorating her tree (or trees — some years, she'd have two). After she moved into a larger home, she began to think it would be nice to have some people in to see her decorations.

Thus was born the annual Christmas dinner, which, like the ornament collection, grew and grew. Now she collects recipes as well as ornaments, trying them out on her co-workers and her husband, searching all year long for the one or two new things she'll add to the menu each year.

This year, one new addition was broiled sushi: She lined three jelly roll pans with cooked sushi rice, which was then topped with furikake and a seafood-and-mushrooms-in-a-sour-cream-mayonnaise mixture. The "sushi" is broiled and served with sheets of Korean-style crisp nori.

Lum prepares for the annual feast like a general marshalling troops for an invasion. She shops year-round, stockpiling ingredients when they're on sale. Shortly before the party, she empties the refrigerator and freezer of anything not party-related, stashing some things at her sister's. She bakes cakes ahead of time and freezes them. She gathers her equipment: her four slow cookers, two ice cream makers, one dozen 9-by-13-inch pans and a half-dozen coolers for the overflow when the refrigerator is full. As is fitting for someone who works as a payroll processor, she uses an Xcel spread sheet to organize her shopping list.

Milton Lum is her second in command, in charge of Christmas lights, making the kalua pork and running out to the grocery store (at 2 in the morning sometimes — thank goodness Safeway is right across the street).

She types up the recipes she plans to use, then makes notes as she tries it out so she can remember the changes she's made — because there are always changes. Like many good cooks, Lum never follows a recipe as it's written. Her usual approach is to get an idea and then go in search of recipes — in magazines, online, among her cookbooks.

"I drive myself crazy. Like for this raspberry sherbet I made, I had seven different versions that I found and I'll take one thing from one recipe and combine it with something from the other," she said.

So confident is she of her skills that she often tries out new dishes at her parties without testing them first. "People will say, 'Oh, that's so good,' and I'll say, 'Is it? I haven't even tried it yet.' But you just get so you know when something is going to come out." She says she gives a recipe three tries; if it doesn't consistently draw compliments, it's out of the collection.

Lum, who hopes to write a cookbook someday, is especially fond of making desserts; last year, between Dec. 17 and Dec. 25, she made 35 different kinds of desserts. She'll often volunteer to make sweets for friends' parties, and she keeps both her office and her husband's office well supplied.

"I tell them, 'You're my guinea pigs,' and they say 'That's fine with us!' "

Reach Wanda A. Adams at wadams@honoluluadvertiser.com.