It's hard to pinpoint the exact moment when an evening of gracious entertaining becomes a sentence of dinner with no parole, but there are a few simple ways to make sure that the cook enjoys the party too.
When planning the menu, include a variety of different types of foods. Be sure to include different textures (crispy, creamy, crunchy, tender) and flavors (sweet, sour, salty, bitter, astringent, pungent, cooling). Serve some cold items (crudites, chilled soups, ice cream or sorbet), some at room temperature (antipasto or other appetizers, cookies or cakes), and some hot (stew, hot entrees, warm brownies or pies). Variety is key, but above all, rely mostly on tried-and-true dishes that are quick and easy. If you want to make a grand impression, go for it once in the meal, rather than trying for a climax at every course.
To develop a shopping and cooking plan, think about what can be cooked ahead and what ingredients will be hard to purchase or store well. Map out a plan for what needs to be done each day leading up to the party (shopping, cooking ahead, freezing, thawing, and so on). Get help to manage the workload. Unless you live with a staff of four in your kitchen, you'll probably need some help, even for a small dinner party.This can be as simple as having guests help with the cooking, or deciding that you will buy the dessert rather than prepare it yourself.
Always avoid last-minute disaster by cooking ahead. If you insist on cooking everything from scratch and want to be able to attend the party as well, it is essential that you prepare as much of the food ahead of time as possible. Freeze whatever you can, and plan dishes that don't require last-minute fussing. Appetizers that use commercially prepared frozen puff pastry are infinitely elegant and keep for weeks in the freezer. Chilled souffles and soups can be made a day ahead and can be ready for service without so much as reheating. Pates can be chill for weeks in the refrigerator, and marinated salads provide brilliant colors and piquant flavors that only get better after a day's sojourn in the fridge.
If you do not have a double oven to cook multiple roasts, prepare the roasts in batches. If you do have a double oven, you can cook multiple roasts at the same time. Halfway through cooking, switch and rotate the position of each roast to compensate for any uneven heat distribution. Keep in mind the recipes are typically written for single, modest-size roasts. Doubling up two small roasts will increase the cooking time slightly. Use an instant-read thermometer to check internal temperatures rather than going solely by cooking time.