How does Catholic Church view the new school of thought on multiplication of bread by Jesus? There is a school of thought going around that Jesus in fact did not multiply bread to feed the people who had gathered to listen to Him, but only prompted the faithful to share whatever eatables they had in stock . But then, we read at Mark 8:18-20 (NRSVCE) : 

" Do  you have eyes, and fail to see? Do you have ears, and fail to hear? And do you not remember? When I broke the five loaves for the five thousand, how many baskets full of broken pieces did you collect?” They said to him, “Twelve.”  “And the seven for the four thousand, how many baskets full of broken pieces did you collect?” And they said to him, “Seven.”

My question is: how does the Catholic Church view the new school of thought which apparently tries to `explain away' two important miracles performed by Jesus ?
Denial of miracles is one characteristic of the heresy of Modernism.

Doctors of the Church did not deny the miraculous nature of the multiplication of the loaves:


The multiplication of the loaves was not effected by way of creation, but by an addition of extraneous matter:The multiplication of the loaves was not effected by way of creation, but by an addition of extraneous matter transformed into loaves; hence Augustine says on Jn 6:1-14: ‘Whence He multiplieth a few grains into harvests, thence in His hands He multiplied the five loaves’: and it is clearly by a process of transformation that grains are multiplied into harvests. (Saint Thomas Aquinas. Summa Theologica III, q. 44, a.4, ad.4)
He who multiplied the five loaves is the same One who multiplies the fruits of the seeds:A great miracle: but we shall not wonder much at what was done, if we give heed to Him That did it. He multiplied the five loaves in the hands of them that brake them, who multiplieth the seeds that grow in the earth, so as that a few grains are sown, and whole barns are filled. But, because he doth this every year, no one marvels. Not the inconsiderableness of what is done, but its constancy takes away admiration of it. But when the Lord did these things, He spake to them that had understanding, not by words only, but even by the miracles themselves. (Saint Augustine. Sermon 130, no. 1)
In multiplying the loaves, Jesus showed his power over material nature:But what is divine is that the five loaves were more than sufficient for five thousand people, for clearly it was not this little food that had satisfied the people, but its multiplication. As you have seen, as though by an irrepressible font abounding from the hands of the distributors the fragments that they had not yet divided, and without daring to touch them with their fingers, the pieces spontaneously appeared. When such things are read, how can we be surprised with the perpetual movement of the waters or become amazed that the liquid fonts flow without ceasing when a solid substance expands in abundance? This happens to make us see that which we ordinarily do not see. By one thing He has manifested with such evidence that he is equally the Author of the others and the Creator of all of material nature, that was not found, but made, and supplies his successive contributions to the production of all things. (Saint Ambrose. Treatise on the Gospel of Saint Luke, bk. VI, no. 84-85)
The remains of the multiplication exceeded as fragments so that the absent might learn of the miracle:‘And He brake and gave to the disciples, and the disciples to the multitude.’ The five loaves He brake and gave, and the five multiplied themselves in the hands of the disciples. And not even here doth He stay the miracle, but He made them even to exceed; to exceed, not as whole loaves, but as fragments; to signify that of those loaves these were remains, and in order that the absent might learn what had been done. (Saint John Chrysostom. Homily on Matthew, Homily XLIX)
The fragments showed that what had taken place was no illusion:And I marvel not only at the quantity of loaves created, but besides the quantity, at the exactness of the surplus, that He caused the superabundance to be neither more nor less than just so much as He willed, fore-seeing how much they would consume; a thing which marked unspeakable power. The fragments then confirmed the matter, showing both these points; that what had taken place was no illusion, and that these were from the loaves by which the people had been fed. (Saint John Chrysostom. Homily on the Gospel of Saint John. Homily XLII)


source: Denzinger-Bergoglio, "Francis and the curious miracle of the non-multiplication of the loaves", which contains more magisterial teachings regarding the necessity of believing Christ's miracles