Add 40g softened butter and 25g powdered sugar into a bowl, mix well with a spatula.
Sift in 60g cake flour, roughly mix with a spatula, then use hands to mix all the ingredients into a dough.
Optionally, use a toothpick to add a little bit of red food coloring to the dough. Use your hands to knead the dough until it looks evenly pink.
Fold a piece of parchment/wax paper in half, place the craquelin dough in between. Use a pin roller to roll the dough into a 6X8 inch rectangle. Keep it in the freezer.
Beat 3 large eggs (about 150g liquid eggs) in a bowl. Sift 70g cake flour onto a piece of parchment/wax paper (in this way you could add the sifted cake flour to the boiling mixture fast).
Add 50g butter, 100g water, 5g sugar, and 1g salt to a saucepot. Bring to a boil over medium-high heat.
Turn heat to medium-low, quickly add in 70g sifted cake flour.
Use a spatula to mix well. Blend and cook the mixture over medium-low heat for about 2 minutes, until the mixture turns into a smooth dough.
Transfer the cooked dough to a large mixing bowl, spread up the dough in the bottom of the bowl so that it cools down faster.
Once the mixture feels warm to touch (instead of hot),add about ¼ cup of eggs, mix well, then add another ¼ cup of eggs mix well.
Then gradually add in eggs (½ tbsp at a time) until the batter becomes smooth and pass the 2-inch V Shape Test (See article above about the test).
Put the batter into a piping bag with a ½-inch round piping tip.
Preheat the oven to 410°F (210°C).
Line a baking pan with a nonstick baking mat or parchment paper. Optionally, dip a 2-inch cookie cutter in flour, print 8 flour circles on the parchment paper.
Keep the piping tip vertical to the parchment paper, leave about ½-inch distance between the piping tip and the parchment paper.
Pipe the batter in the center of each circle without moving the piping tip. Pipe until the batter expand into a 2-inch-diameter mound, gently lift the piping tip.
Take out craquelin dough from the freezer, use a 2-inch cookie cutter to cut out 8 circles.
Place a craquelin circle on top of each piped dough. Do not press the craquelin circle.
Bake at 410°F (210°C) for 15 minutes. Reduce oven temperature to 355°F (180°C), bake for 15 more minutes. Don't open the oven door to peek.
Take out puffs from the oven to cool on a rack. Fill with pastry cream (see recipe; or whipped cream), decorate with strawberries or other fruits of your choice. See article above for "3 different ways to fill cream puffs".