With a mixer, beat the butter until fluffy, about 3 minutes. Add brown sugar & mix to incorporate. Add whole egg & continue beating, scraping down sides of the bowl, for about 5 minutes.
In a separate bowl, sift together the flour, baking powder, baking soda & salt. With mixer at low speed, add 1/4 of flour mixture to butter & sugar mixture. Add 1/4 cup buttermilk. Continue alternating between flour & buttermilk additions, beating well after each. Mix in liqueur & then add 1/2 cup macadamia nuts. Pour into a greased & floured 9" baking pan.
In a small mixing bowl, beat cream & egg yolk together. Pour over batter. Combine remaining macadamia nuts, sugar & orange zest. Sprinkle over batter.
Preheat oven to 350°. Bake 40-50 minutes until center springs back when touched lightly. Let cool 20-30 minutes before cutting.~~From Above & Beyond Parlsey.

Regular chocolate should work with these too:
WHITE CHOCOLATE MACADAMIA NUT COOKIES (2-3 dozen)
2 cups flour
1 tsp baking soda
1 1/2 tsp salt
1/2 cup butter
1 cup brown sugar
1/2 cup sugar
2 eggs
1 tsp vanilla
1 cup chopped macadamia nuts
9-12 oz white chocolate, broken into chunks

Combine first 3 ingredients in a small bowl, & set aside. Cream butter & sugars. Add eggs & vanilla. Add flour mixture, nuts & white chocolate. Drop by teaspoonfuls onto cookie sheets. Bake in a preheated 350° oven for 15-20 minutes.~~

I've used macadamia nuts or pecans in this one:
FUDGE ECSTASIES (about 365)
12 oz semisweet chocolate chips, divided
2 squares (1 oz each) unsweetened chocolate
2 TBL butter or margarine
1/4 cup flour
1/4 tsp baking powder
Pinch of salt
2 eggs
2/3 cup sugar
1 tsp vanilla
1 cup chopped nuts

In a medium sauepan, heat 1 cup of the chocolate chips, the unsweetened chocolate & the butter until melted, stirring constantly. Pour into a large bowl & set aside to cool slightly.
In a separate bowl, mix the flour, baking powder & salt. Add the eggs, sugar & vanilla to the cooled chocolate mixture & beat well. Add the flour mixture & beat thoroughly. Stir in the remaining chocolate bits & the nuts.
Drop the batter by teaspoonfuls onto lightly greased cookie sheets. Bake in a preheated 350° oven for 8-10 minutes or until the edges are firm & the surface is dull & cracked. Cool for 1 minute before removing from the sheets. Place on racks to cool thoroughly.~~ From Hospitality.

Macadamia Cookies
1 cup brown sugar
1 egg
1/2 cup oil
1 teaspoon vanilla
1/2 cup self raising flour, sifted
1 cup plain flour, sifted
1 1/2 cups chopped roasted macadamia nuts
3/4 cup toasted coconut
1 cup white chocolate pieces

Beat sugar and egg together until light and fluffy, add oil and vanilla. Stir in flours and mix well. Fold through the macadamia nuts, coconut and chocolate pieces. Chill mixture for 30 minutes. Shape mixture into about 30 small balls and bake on a tray at 180C for 10-12 minutes or until lightly browned. Cool on tray.

Hawaiian Muffins
2 cups flour
1/3 cup sugar
2 teaspoons baking powder
1/2 teaspoon salt
1 cup salted roasted chopped macadamia nuts
2/3 cup flaked coconut
1/2 cup chopped dried pineapple
3/4 cup milk
1/2 cup melted butter or margarine
1 lightly beaten egg
1 teaspoon vanilla

Preheat oven to 200C. Combine first 4 ingredients, stir in next 3 ingredients to coat. In another bowl mix together the remaining ingredients. Add dry mix to wet mix until just combined. Spoon batter into greased muffin tins and bake 15-20 minutes or until done. Makes 12. These muffins freeze well.