So easy and always good! Combine 7 oz powdered sugar and 2-3 tbs liquid to form a glaze. Dip muffins in the glaze and let the excess drip off.
For flavor :
Combine powdered sugar with lemon, orange or cherry juice, or else with rum or liqueur.
For color : 
Mix water with a little food coloring, creme de menthe or green syrup, blue curacao or light-blue syrup, or red creme de cassis.
For pizza :
Before it dries, sprinkle sugar glaze with colored sugar and sprinkles, or with chopped pistachios. "Paint" dried sugar glaze with colored frosting in tubes.. 

A chocolate coating makes muffins supremely seductive: chop up 7 oz white, milk, or semisweet couverture or coating chocolate and melt in a double boiler. Dip muffins in the chocolate and let the excess drip off.
Shiny chocolate glaze : 
Combine 1 egg, 1 tbs powdered sugar, and 1 tbs cocoa powder. Add 5 tsp coconut oil and stir into the egg-sugar-cocoa mixture. Dip muffins in mixture and refrigerate.
For sprinkling :
Dark chocolate sprinkles on white or light toppings, and chocolate-covered coffee beans on any topping. 

Creams made from dairy products make velvety smooth toppings and fantastic sides for muffins.
Chocolate nut cream :
Stir together ⅔ cup cream cheese, 2 tbs hazelnut butter (from a jar). 2 tbs chopped chocolate, 1 tbs powdered sugar. 2 tbs chocolate liqueur, and 2 tbs softened butter until smooth. Sprinkle with ground hazelnuts.
Mascarpone and fruit cream :
Combine 7 oz mascarpone. 3 tbs powdered sugar, pulp from l vanilla bean, and 5 tbs pureed fruit such as strawberries, raspberries, or mangos.
Herb Ricotta :
Combine 1 cup ricotta cheese, 3 tbs sour cream, 1 tsp mustard, and 3 tbs each of chopped parsley, dill, and basil. Season to taste with salt and pepper. 

A jelly coating gives muffins a beautiful shine: 
In a saucepan, heat 3-4 tbs apricot, raspberry or currant jelly, and spread evenly over warm muffins.
Glaze with a kick :
Combine 1-2 tbs apricot or orange liqueur with the jam.
Fine decorating :
Before it dries, sprinkle glaze with orange zest, lemon zest, or finely diced, candied fruit.

A creamy topping puts a crown on each little muffin. Simply beat 7 oz cream with 2-3 tbs powdered sugar until stiff.
Cinnamon cream :
Beat 7 oz cream with 1 tsp vanilla extract and ¼ tsp cinnamon until stiff.
Chocolate cream :
Melt 3½ tbs crumbled semisweet chocolate in 7 oz cream. Refrigerate overnight and on the following day, beat until stiff.
Coffee cream :
Dissolve 2 tsp instant coffee in 3 tbs hot water and let cool. Beat 7 oz cream and 2 tbs sugar until stiff, and add coffee one spoonful at a time.