Iced (or Hot) Spinach and Pea Soup Chicken Breast en Brochette Marinated Potatoes and Artichoke Hearts Watermelon Chunks and Buttery Sugar Cookies

JUNE IS THE time for picnicking, before the heat settles in and when the ants are less pestiferous than they surely will be as summer takes over. Or so we hope. This transportable meal would make a dashing picnic, whether at lakeside, on the beach, in a park or at the table in your own garden.

To begin the picnic, there is an assertive chilled spinach and pea soup poured from thermoses into mugs. Fresh mint can be snipped into tiny slivers at home and spinkled on the soup when it is served. Slightly bitey and a lovely green, the soup can also be served hot in winter. The main course consists of chunks of chicken breast left on the small skewers on which the meat was broiled, to more comfortably fit into a basket. Spiked with a tasty marinade of lime juice, white wine, olive oil, garlic and tarragon, the chicken is at its best at room temperature. With it is a handsome, subtly sauced salad of cold halved red potatoes with their skins left on, the better to contrast in color with the accompanying artichoke hearts and green onion speckles. The meal ends with seeded watermelon chunks, or any other edible fresh fruit, accompanied by buttery sugar cookies.

The soup, which balances the lightness of spinach with the density of peas, is quickly made one or even two days in advance, since it seems to improve with a little time. Onions are softened in butter, with some flour and a bit of curry cooked in the mixture for a minute or two to tone down the spice's rawness. Defrosted whole leaf spinach and its liquid plus frozen peas are then added along with some water and the vegetables are cooked for a few minutes. The whole batch is pure'ed in a food processor and returned to the pan along with chicken broth and milk. After this is cooked, the soup is cooled and then chilled, ready to pack. Thermoses can be chilled by filling them with ice cubes for half an hour. The ice is discarded and the soup poured into the cold containers just before setting out.

The boneless skinless chicken breasts must be trimmed of all gristle before they are cut into chunks. Once this is done, the rest of the preparation takes only minutes. The pieces marinate overnight in the refrigerator, a process that, because of the lime juice in the marinade, "cooks" them to a certain extent.. The morning of the picnic, the chicken chunks are strung onto skewers, and grilled quickly.

The potato-artichoke salad is made the night before and held in the refrigerator. This salad is best eaten within a day after it is made: it loses flavor if it waits any longer. I have used both frozen artichoke hearts, which are not always easy to find, and canned hearts, and find very little difference in quality if the canned vegetable is washed thoroughly under cold running water to rid it of any metallic taste. The artichokes are then gently squeezed of excess liquid and quartered before they are added to the potatoes. Be careful not to overcook the potatoes. Test frequently with a long, thin knife to avoid the soggy, crumbly mess that potatoes turn into with too much boiling. The combination of white wine vinegar and white wine with olive oil makes a delicate, pleasant and, most important, complimentary dressing.

For adult picnics, watermelon should be cut into manageable chunks and seeded at home. However, children should be provided with whole slices of the fruit and the opportunity to spit seeds, particularly if the ideal location of a back porch can be provided for this cherished occupation. The sugar cookies, which can be made a couple of days in advance and stored in a tight container, are very good with any fruit. They are particularly satisfactory if you have a small child as a helper, since once the butter and sugar have been creamed, the rest is a matter of mushing flour into the butter mixture with the fingers and then rolling balls in hands. Very satisfactory for the mud-pie set. They take no time to make, even less to cook and are very good indeed. ICED (OR HOT) SPINACH AND PEA SOUP (8 Servings) 1 medium-large onion, minced 2 tablespoons butter 2 tablespoons flour 1 teaspoon madras curry powder 10-ounce package frozen whole leaf spinach, defrosted with liquid reserved 10-ounce package frozen green peas 2 cups water 2 14 1/2 ounce cans chicken broth 2 cups milk Salt and pepper to taste 1 1/2 tablespoons minced fresh mint leaves, optional

Cook the minced onion in the butter in a saucepan until the onions are soft and transparent but not colored, about 10 minutes. Add the flour and curry powder and cook, stirring constantly, for 2 minutes. Then add the spinach, its juices, the peas and 2 cups of water. Bring to boil, lower heat and cook for 10 minutes, stirring occasionally. Turn the mixture into a food processor bowl and process, stopping to scrape down the sides of the bowl at least once, until the vegetables are pure'ed. Return the pure'e to the saucepan, stir in the chicken broth, milk, salt and pepper and bring to a boil, stirring. Pour the soup into a large bowl, cool to room temperature and refrigerate overnight or longer. When the soup is thoroughly chilled, taste again and adjust seasonings. To serve, pour soup into mugs or bowls and garnish with minced mint leaves, if desired. COLD CHICKEN BREAST EN BROCHETTE (8 servings) 2 1/4 pounds boneless, skinned chicken breasts (about 3 whole breasts) 3 tablespoons lime juice 1/4 cup white wine 1/4 cup olive oil 1 clove garlic, crushed 1 teaspoon dried tarragon Salt and pepper to taste Paprika

Dry the chicken breasts and cut them into 2-inch chunks, removing tendons and gristle, to make about 35 to 40 chunks. Combine the lime juice, white wine, olive oil, crushed garlic, tarragon and salt and pepper to taste. Add the chunks of chicken, stir, cover and refrigerate for several hours or overnight. If the marinade does not cover the chicken, stir when you think of it.

To cook the chicken, remove the chunks from the marinade and string them onto 8 large or 16 small skewers, leaving ample room between the chunks so they will brown nicely. Sprinkle with paprika and arrange the skewers about an inch apart on a large roasting pan. Broil for 3 minutes. Remove the pan, turn the skewers, baste with the marinade and return to the broiler for another 3 1/2 minutes. Remove the pan and cut through one of the chunks. If the juices run pink, cook the chicken for another minute. The chicken is done when the juices run yellow. Leave the chicken chunks on the skewers, if desired. Cool and pack in the picnic hamper. Or refrigerate and bring to room temperature before serving. MARINATED POTATOES AND ARTICHOKE HEARTS (8 servings) 2 pounds small or medium red bliss potatoes, unpeeled 2 14-ounce cans (8 1/2 ounces drained weight) artichoke hearts, rinsed well under cold running water, drained and squeezed to get rid of excess water and quartered, or 2 9-ounce packages frozen artichoke hearts, cooked according to package directions, drained, cooled and quartered 3 tablespoons dry white wine 4 1/2 teaspoons white wine vinegar 3 tablespoons olive oil 5 scallions, cleaned with some green parts remaining and sliced very thinly Salt and pepper to taste

Wash the potatoes and cook them in boiling water until they test just done when pierced with a long, thin knife. Drain well. Do not remove the skins. Cut the potatoes in half if they are small or quarter them if they are medium-sized. Place in a large bowl. Add the quartered artichoke hearts and the remaining ingredients to the warm potatoes. Toss to mix well, cool to room temperature, cover and refrigerate overnight. Serve at room temperature. TESSA'S BUTTERY SUGAR COOKIES (Makes about 60) 1/2 pound butter 5 tablespoons sugar 1 teaspoon vanilla 2 cups flour About 1/3 cup sugar for rolling the baked cookies

Cream the butter and sugar with an electric mixer until light and fluffy. Beat in the vanilla. Work in the flour with the fingers. Roll into balls about 3/4 inch in diameter and place on a cookie sheet about 1 inch apart. The cookies will swell by 1/3 as they bake. Place in a 350-degree oven for about 5 minutes, or until the cookies are pale gold. Roll in additional sugar, cool and store in a tight container.